1105 lines
36 KiB
C++
1105 lines
36 KiB
C++
// RH_ASK.cpp
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//
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// Copyright (C) 2014 Mike McCauley
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// $Id: RH_ASK.cpp,v 1.32 2020/08/04 09:02:14 mikem Exp $
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#include <RH_ASK.h>
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#include <RHCRC.h>
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#ifndef __SAMD51__
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#if (RH_PLATFORM == RH_PLATFORM_STM32)
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// Maple etc
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HardwareTimer timer(MAPLE_TIMER);
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#elif defined(ARDUINO_ARCH_RP2040)
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#elif defined(BOARD_NAME)
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// ST's Arduino Core STM32, https://github.com/stm32duino/Arduino_Core_STM32
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#if defined(RH_HW_TIMER)
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// Can define your own timer name based on macros defs passed to compiler eg in platformio.ini
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HardwareTimer timer(RH_HW_TIMER);
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#else
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HardwareTimer timer(TIM1);
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#endif
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#elif defined(ARDUINO_ARCH_STM32) || defined(ARDUINO_ARCH_STM32F1) || defined(ARDUINO_ARCH_STM32F3) || defined(ARDUINO_ARCH_STM32F4)
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// Roger Clark Arduino STM32, https://github.com/rogerclarkmelbourne/Arduino_STM32
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// And stm32duino
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HardwareTimer timer(1);
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#elif defined(ARDUINO_UNOR4_MINIMA) || defined(ARDUINO_UNOR4_WIFI)
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#include "FspTimer.h"
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FspTimer ask_timer;
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#elif (RH_PLATFORM == RH_PLATFORM_ARDUINO) && defined(RH_CUBE_CELL_BOARD)
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static TimerEvent_t timer;
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#endif
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#if (RH_PLATFORM == RH_PLATFORM_ESP32)
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// Michael Cain
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DRAM_ATTR hw_timer_t * timer;
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//jPerotto Non-constant static data from ESP32 https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/general-notes.html#dram-data-ram
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#define RH_DRAM_ATTR DRAM_ATTR
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#else
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#define RH_DRAM_ATTR
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#endif
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// RH_ASK on Arduino uses Timer 1 to generate interrupts 8 times per bit interval
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// Define RH_ASK_ARDUINO_USE_TIMER2 if you want to use Timer 2 instead of Timer 1 on Arduino
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// You may need this to work around other libraries that insist on using timer 1
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// Should be moved to header file
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//#define RH_ASK_ARDUINO_USE_TIMER2
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// RH_ASK on ATtiny8x uses Timer 0 to generate interrupts 8 times per bit interval.
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// Timer 0 is used by Arduino platform for millis()/micros() which is used by delay()
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// Uncomment the define RH_ASK_ATTINY_USE_TIMER1 bellow, if you want to use Timer 1 instead of Timer 0 on ATtiny
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// Timer 1 is also used by some other libraries, e.g. Servo. Alway check usage of Timer 1 before enabling this.
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// Should be moved to header file
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//#define RH_ASK_ATTINY_USE_TIMER1
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// Interrupt handler uses this to find the most recently initialised instance of this driver
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static RH_ASK* thisASKDriver;
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// 4 bit to 6 bit symbol converter table
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// Used to convert the high and low nybbles of the transmitted data
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// into 6 bit symbols for transmission. Each 6-bit symbol has 3 1s and 3 0s
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// with at most 3 consecutive identical bits
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RH_DRAM_ATTR static uint8_t symbols[] =
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{
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0xd, 0xe, 0x13, 0x15, 0x16, 0x19, 0x1a, 0x1c,
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0x23, 0x25, 0x26, 0x29, 0x2a, 0x2c, 0x32, 0x34
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};
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// This is the value of the start symbol after 6-bit conversion and nybble swapping
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#define RH_ASK_START_SYMBOL 0xb38
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RH_ASK::RH_ASK(uint16_t speed, uint8_t rxPin, uint8_t txPin, uint8_t pttPin, bool pttInverted)
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:
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_speed(speed),
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_rxPin(rxPin),
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_txPin(txPin),
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_pttPin(pttPin),
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_rxInverted(false),
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_pttInverted(pttInverted)
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{
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// Initialise the first 8 nibbles of the tx buffer to be the standard
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// preamble. We will append messages after that. 0x38, 0x2c is the start symbol before
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// 6-bit conversion to RH_ASK_START_SYMBOL
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uint8_t preamble[RH_ASK_PREAMBLE_LEN] = {0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x38, 0x2c};
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memcpy(_txBuf, preamble, sizeof(preamble));
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}
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bool RH_ASK::init()
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{
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if (!RHGenericDriver::init())
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return false;
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thisASKDriver = this;
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#if (RH_PLATFORM == RH_PLATFORM_GENERIC_AVR8)
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#ifdef RH_ASK_PTT_PIN
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RH_ASK_PTT_DDR |= (1<<RH_ASK_PTT_PIN);
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RH_ASK_TX_DDR |= (1<<RH_ASK_TX_PIN);
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RH_ASK_RX_DDR &= ~(1<<RH_ASK_RX_PIN);
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#else
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RH_ASK_TX_DDR |= (1<<RH_ASK_TX_PIN);
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RH_ASK_RX_DDR &= ~(1<<RH_ASK_RX_PIN);
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#endif
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#else
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// Set up digital IO pins for arduino
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pinMode(_txPin, OUTPUT);
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pinMode(_rxPin, INPUT);
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pinMode(_pttPin, OUTPUT);
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#endif
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// Ready to go
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setModeIdle();
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timerSetup();
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return true;
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}
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// Put these prescaler structs in PROGMEM, not on the stack
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#if (RH_PLATFORM == RH_PLATFORM_ARDUINO) || (RH_PLATFORM == RH_PLATFORM_GENERIC_AVR8) || (RH_PLATFORM == RH_PLATFORM_ATTINY)
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#if defined(RH_ASK_ARDUINO_USE_TIMER2)
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// Timer 2 has different prescalers
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PROGMEM static const uint16_t prescalers[] = {0, 1, 8, 32, 64, 128, 256, 3333};
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#elif defined(RH_ASK_ATTINY_USE_TIMER1) && defined(TCCR1)
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// ATtiny85 Timer1 prescalers
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PROGMEM static const uint16_t prescalers[] = {0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 1024, 2048, 4096, 8192, 16384, 33333};
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#else
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PROGMEM static const uint16_t prescalers[] = {0, 1, 8, 64, 256, 1024, 3333};
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#endif
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#define NUM_PRESCALERS (sizeof(prescalers) / sizeof( uint16_t))
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#endif
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// Common function for setting timer ticks @ prescaler values for speed
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// Returns prescaler index into {0, 1, 8, 64, 256, 1024} array
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// and sets nticks to compare-match value if lower than max_ticks
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// returns 0 & nticks = 0 on fault
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uint8_t RH_ASK::timerCalc(uint16_t speed, uint16_t max_ticks, uint16_t *nticks)
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{
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#if (RH_PLATFORM == RH_PLATFORM_ARDUINO && !defined(ARDUINO_ARCH_RP2040) && !defined(RH_CUBE_CELL_BOARD)) || (RH_PLATFORM == RH_PLATFORM_GENERIC_AVR8) || (RH_PLATFORM == RH_PLATFORM_ATTINY)
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// Clock divider (prescaler) values - 0/3333: error flag
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uint8_t prescaler; // index into array & return bit value
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unsigned long ulticks; // calculate by ntick overflow
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// Div-by-zero protection
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if (speed == 0)
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{
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// signal fault
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*nticks = 0;
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return 0;
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}
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// test increasing prescaler (divisor), decreasing ulticks until no overflow
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// 1/Fraction of second needed to xmit one bit
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unsigned long inv_bit_time = ((unsigned long)speed) * 8;
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for (prescaler = 1; prescaler < NUM_PRESCALERS; prescaler += 1)
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{
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// Integer arithmetic courtesy Jim Remington
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// 1/Amount of time per CPU clock tick (in seconds)
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uint16_t prescalerValue;
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memcpy_P(&prescalerValue, &prescalers[prescaler], sizeof(uint16_t));
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unsigned long inv_clock_time = F_CPU / ((unsigned long)prescalerValue);
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// number of prescaled ticks needed to handle bit time @ speed
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ulticks = inv_clock_time / inv_bit_time;
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// Test if ulticks fits in nticks bitwidth (with 1-tick safety margin)
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if ((ulticks > 1) && (ulticks < max_ticks))
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break; // found prescaler
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// Won't fit, check with next prescaler value
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}
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// Check for error
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if ((prescaler == 6) || (ulticks < 2) || (ulticks > max_ticks))
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{
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// signal fault
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*nticks = 0;
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return 0;
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}
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*nticks = ulticks;
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return prescaler;
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#else
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return 0; // not implemented or needed on other platforms
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#endif
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}
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#if defined(RH_PLATFORM_ARDUINO) && defined(ARDUINO_ARCH_RP2040)
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void set_pico_alarm(uint32_t speed)
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{
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uint32_t period = (1000000 / 8) / speed; // In microseconds
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uint64_t target = timer_hw->timerawl + period;
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timer_hw->alarm[RH_ASK_PICO_ALARM_NUM] = (uint32_t) target;
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}
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#endif
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// The idea here is to get 8 timer interrupts per bit period
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void RH_ASK::timerSetup()
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{
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#if (RH_PLATFORM == RH_PLATFORM_GENERIC_AVR8)
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uint16_t nticks;
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uint8_t prescaler = timerCalc(_speed, (uint16_t)-1, &nticks);
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if (!prescaler) return;
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_COMB(TCCR,RH_ASK_TIMER_INDEX,A)= 0;
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_COMB(TCCR,RH_ASK_TIMER_INDEX,B)= _BV(WGM12);
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_COMB(TCCR,RH_ASK_TIMER_INDEX,B)|= prescaler;
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_COMB(OCR,RH_ASK_TIMER_INDEX,A)= nticks;
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_COMB(TI,MSK,RH_ASK_TIMER_INDEX)|= _BV(_COMB(OCIE,RH_ASK_TIMER_INDEX,A));
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#elif (RH_PLATFORM == RH_PLATFORM_MSP430) // LaunchPad specific
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// Calculate the counter overflow count based on the required bit speed
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// and CPU clock rate
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uint16_t ocr1a = (F_CPU / 8UL) / _speed;
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// This code is for Energia/MSP430
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TA0CCR0 = ocr1a; // Ticks for 62,5 us
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TA0CTL = TASSEL_2 + MC_1; // SMCLK, up mode
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TA0CCTL0 |= CCIE; // CCR0 interrupt enabled
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#elif (RH_PLATFORM == RH_PLATFORM_STM32L0)
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Serial.println("STM32L0 RH_ASK NOT YET IMPLEMENTED ");
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#elif (RH_PLATFORM == RH_PLATFORM_STM32) || defined(ARDUINO_ARCH_STM32) || defined(ARDUINO_ARCH_STM32F1) || defined(ARDUINO_ARCH_STM32F3) || defined(ARDUINO_ARCH_STM32F4)
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// Maple etc
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// or rogerclarkmelbourne/Arduino_STM32
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// or stm32duino
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// Pause the timer while we're configuring it
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timer.pause();
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#ifdef BOARD_NAME
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// ST's Arduino Core STM32, https://github.com/stm32duino/Arduino_Core_STM32
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// Declaration of the callback function changed in 1.9. Sigh
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#if (STM32_CORE_VERSION >= 0x01090000)
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void interrupt();
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#else
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void interrupt(HardwareTimer*); // defined below
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#endif
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uint16_t us=(1000000/8)/_speed;
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timer.setMode(1, TIMER_OUTPUT_COMPARE);
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timer.setOverflow(us, MICROSEC_FORMAT);
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timer.setCaptureCompare(1, us - 1, MICROSEC_COMPARE_FORMAT);
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#if (STM32_CORE_VERSION >= 0x01090000)
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timer.attachInterrupt(interrupt);
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#else
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timer.attachInterrupt(1, interrupt);
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#endif
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#else
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void interrupt(); // defined below
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// Roger Clark Arduino STM32, https://github.com/rogerclarkmelbourne/Arduino_STM32
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timer.setPeriod((1000000/8)/_speed);
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// Set up an interrupt on channel 1
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timer.setChannel1Mode(TIMER_OUTPUT_COMPARE);
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timer.setCompare(TIMER_CH1, 1); // Interrupt 1 count after each update
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void interrupt(); // defined below
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timer.attachCompare1Interrupt(interrupt);
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#endif
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// Refresh the timer's count, prescale, and overflow
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timer.refresh();
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// Start the timer counting
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timer.resume();
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#elif (RH_PLATFORM == RH_PLATFORM_ATTINY)
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// figure out prescaler value and counter match value
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// REVISIT: does not correctly handle 1MHz clock speeds, only works with 8MHz clocks
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// At 1MHz clock, get 1/8 of the expected baud rate
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uint16_t nticks;
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uint8_t prescaler = timerCalc(_speed, (uint8_t)-1, &nticks);
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if (!prescaler)
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return; // fault
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#if defined(RH_ASK_ATTINY_USE_TIMER1)
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#if defined(TCCR1)
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// ATtiny85
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TCCR1 = 0;
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TCCR1 = _BV(CTC1); // Turn on CTC mode / Output Compare pins disconnected
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// convert prescaler index to TCCR1 prescaler bits CS10, CS11, CS12, CS13
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TCCR1 |= prescaler; // set CS10, CS11, CS12, CS13 (other bits not needed)
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// Number of ticks to count before firing interrupt
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OCR1A = uint8_t(nticks);
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// Number of ticks to count before counter reset (CTC mode)
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OCR1C = uint8_t(nticks);
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// Synchronous mode and PLL disabled
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PLLCSR = 0;
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// Set mask to fire interrupt when OCF1A bit is set in TIFR1
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TIMSK |= _BV(OCIE1A);
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#else //TCCR1
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// ATtiny84
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TCCR1A = 0; // Output Compare pins disconnected
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TCCR1B = _BV(WGM12); // Turn on CTC mode
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// convert prescaler index to TCCRnB prescaler bits CS10, CS11, CS12
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TCCR1B |= prescaler;
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TCCR1C = 0;
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// Caution: special procedures for setting 16 bit regs
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// is handled by the compiler
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OCR1A = nticks;
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//enable interupt
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TIMSK1 |= _BV(OCIE1A);
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#endif //
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#else //RH_ASK_ATTINY_USE_TIMER1
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TCCR0A = 0;
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TCCR0A = _BV(WGM01); // Turn on CTC mode / Output Compare pins disconnected
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// convert prescaler index to TCCRnB prescaler bits CS00, CS01, CS02
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TCCR0B = 0;
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TCCR0B = prescaler; // set CS00, CS01, CS02 (other bits not needed)
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// Number of ticks to count before firing interrupt
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OCR0A = uint8_t(nticks);
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// Set mask to fire interrupt when OCF0A bit is set in TIFR0
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#ifdef TIMSK0
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// ATtiny84
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TIMSK0 |= _BV(OCIE0A);
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#else
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// ATtiny85
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TIMSK |= _BV(OCIE0A);
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#endif
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#endif //RH_ASK_ATTINY_USE_TIMER1
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#elif (RH_PLATFORM == RH_PLATFORM_ATTINY_MEGA)
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// If your processor does not have a TCB1, you can change the timer used in RadioHead.h
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volatile TCB_t* timer = &RH_ATTINY_MEGA_ASK_TIMER;
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// Calculate compare value
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uint32_t compare_val = F_CPU / _speed / 8 - 1;
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// If compare larger than 16bits, need to prescale (will be DIV64)
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if (compare_val > 0xFFFF)
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{
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// recalculate with new prescaler
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compare_val = F_CPU / _speed / 8 / 64 - 1;
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// Prescaler needed
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timer->CTRLA = TCB_CLKSEL_CLKTCA_gc;
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}
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else
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{
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// No prescaler needed
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timer->CTRLA = TCB_CLKSEL_CLKDIV1_gc;
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}
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// Timer to Periodic interrupt mode
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// This write will also disable any active PWM outputs
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timer->CTRLB = TCB_CNTMODE_INT_gc;
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// Write compare register
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timer->CCMP = compare_val;
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// Enable interrupt
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timer->INTCTRL = TCB_CAPTEI_bm;
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// Enable Timer
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timer->CTRLA |= TCB_ENABLE_bm;
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#elif (RH_PLATFORM == RH_PLATFORM_ARDUINO) && defined(RH_CUBE_CELL_BOARD)
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// Arduino CubeCell board 1.0.0 has non-standard timer support
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// Forward declaration of the callback below
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void timer_callback();
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TimerInit(&timer, timer_callback);
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// Sigh: This timer takes the timeout in milliseconds, not microseconds. That means the fastest bit rate
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// we can support is 1000 / 8 = 125 bits per second.
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uint32_t period = (1000 / 8) / _speed; // In milliseconds
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TimerSetValue(&timer, period); // mseconds
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TimerStart(&timer);
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#elif (RH_PLATFORM == RH_PLATFORM_ARDUINO) // Arduino specific
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#if defined(__arm__) && defined(CORE_TEENSY)
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// on Teensy 3.0 (32 bit ARM), use an interval timer
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IntervalTimer *t = new IntervalTimer();
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void TIMER1_COMPA_vect(void);
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t->begin(TIMER1_COMPA_vect, 125000 / _speed);
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#elif defined (__arm__) && defined(ARDUINO_ARCH_SAMD)
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// Arduino Zero
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#define RH_ASK_ZERO_TIMER TC3
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// Clock speed is 48MHz, prescaler of 64 gives a good range of available speeds vs precision
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#define RH_ASK_ZERO_PRESCALER 64
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#define RH_ASK_ZERO_TIMER_IRQ TC3_IRQn
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// Enable clock for TC
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REG_GCLK_CLKCTRL = (uint16_t) (GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_ID(GCM_TCC2_TC3)) ;
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while ( GCLK->STATUS.bit.SYNCBUSY == 1 ); // wait for sync
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// The type cast must fit with the selected timer mode
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TcCount16* TC = (TcCount16*)RH_ASK_ZERO_TIMER; // get timer struct
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TC->CTRLA.reg &= ~TC_CTRLA_ENABLE; // Disable TC
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while (TC->STATUS.bit.SYNCBUSY == 1); // wait for sync
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TC->CTRLA.reg |= TC_CTRLA_MODE_COUNT16; // Set Timer counter Mode to 16 bits
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while (TC->STATUS.bit.SYNCBUSY == 1); // wait for sync
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TC->CTRLA.reg |= TC_CTRLA_WAVEGEN_MFRQ; // Set TC as Match Frequency
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while (TC->STATUS.bit.SYNCBUSY == 1); // wait for sync
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// Compute the count required to achieve the requested baud (with 8 interrupts per bit)
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uint32_t rc = (VARIANT_MCK / _speed) / RH_ASK_ZERO_PRESCALER / 8;
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TC->CTRLA.reg |= TC_CTRLA_PRESCALER_DIV64; // Set prescaler to agree with RH_ASK_ZERO_PRESCALER
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while (TC->STATUS.bit.SYNCBUSY == 1); // wait for sync
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TC->CC[0].reg = rc; // FIXME
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while (TC->STATUS.bit.SYNCBUSY == 1); // wait for sync
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// Interrupts
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TC->INTENSET.reg = 0; // disable all interrupts
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TC->INTENSET.bit.MC0 = 1; // enable compare match to CC0
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// Enable InterruptVector
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NVIC_ClearPendingIRQ(RH_ASK_ZERO_TIMER_IRQ);
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NVIC_EnableIRQ(RH_ASK_ZERO_TIMER_IRQ);
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// Enable TC
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TC->CTRLA.reg |= TC_CTRLA_ENABLE;
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while (TC->STATUS.bit.SYNCBUSY == 1); // wait for sync
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#elif defined(__arm__) && defined(ARDUINO_SAM_DUE)
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// Arduino Due
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// Clock speed is 84MHz
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// Due has 9 timers in 3 blocks of 3.
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// We use timer 1 TC1_IRQn on TC0 channel 1, since timers 0, 2, 3, 4, 5 are used by the Servo library
|
|
#define RH_ASK_DUE_TIMER TC0
|
|
#define RH_ASK_DUE_TIMER_CHANNEL 1
|
|
#define RH_ASK_DUE_TIMER_IRQ TC1_IRQn
|
|
pmc_set_writeprotect(false);
|
|
pmc_enable_periph_clk(RH_ASK_DUE_TIMER_IRQ);
|
|
|
|
// Clock speed 4 can handle all reasonable _speeds we might ask for. Its divisor is 128
|
|
// and we want 8 interrupts per bit
|
|
uint32_t rc = (VARIANT_MCK / _speed) / 128 / 8;
|
|
TC_Configure(RH_ASK_DUE_TIMER, RH_ASK_DUE_TIMER_CHANNEL,
|
|
TC_CMR_WAVE | TC_CMR_WAVSEL_UP_RC | TC_CMR_TCCLKS_TIMER_CLOCK4);
|
|
TC_SetRC(RH_ASK_DUE_TIMER, RH_ASK_DUE_TIMER_CHANNEL, rc);
|
|
// Enable the RC Compare Interrupt
|
|
RH_ASK_DUE_TIMER->TC_CHANNEL[RH_ASK_DUE_TIMER_CHANNEL].TC_IER = TC_IER_CPCS;
|
|
NVIC_ClearPendingIRQ(RH_ASK_DUE_TIMER_IRQ);
|
|
NVIC_EnableIRQ(RH_ASK_DUE_TIMER_IRQ);
|
|
TC_Start(RH_ASK_DUE_TIMER, RH_ASK_DUE_TIMER_CHANNEL);
|
|
|
|
#elif defined(ARDUINO_ARCH_RP2040)
|
|
// Per https://emalliab.wordpress.com/2021/04/18/raspberry-pi-pico-arduino-core-and-timers/
|
|
hw_set_bits(&timer_hw->inte, 1u << RH_ASK_PICO_ALARM_NUM);
|
|
void picoInterrupt(); // Forward declaration of interrupt handler
|
|
irq_set_exclusive_handler(RH_ASK_PICO_ALARM_IRQ, picoInterrupt);
|
|
irq_set_enabled(RH_ASK_PICO_ALARM_IRQ, true);
|
|
set_pico_alarm(_speed);
|
|
|
|
#elif defined(ARDUINO_UNOR4_MINIMA) || defined(ARDUINO_UNOR4_WIFI)
|
|
uint8_t timer_type = GPT_TIMER;
|
|
int8_t tindex = FspTimer::get_available_timer(timer_type);
|
|
if (tindex < 0)
|
|
tindex = FspTimer::get_available_timer(timer_type, true);
|
|
|
|
if (tindex < 0)
|
|
return;
|
|
|
|
FspTimer::force_use_of_pwm_reserved_timer();
|
|
void timer_callback(timer_callback_args_t __attribute((unused)) *p_args); // Forward declaration
|
|
if (!ask_timer.begin(TIMER_MODE_PERIODIC, timer_type, tindex, _speed * 8, 0.0f, timer_callback))
|
|
return;
|
|
|
|
if (!ask_timer.setup_overflow_irq())
|
|
return;
|
|
|
|
if (!ask_timer.open())
|
|
return;
|
|
|
|
if (!ask_timer.start())
|
|
return;
|
|
|
|
#else
|
|
uint16_t nticks; // number of prescaled ticks needed
|
|
uint8_t prescaler; // Bit values for CS0[2:0]
|
|
|
|
// This is the path for most Arduinos
|
|
// figure out prescaler value and counter match value
|
|
#if defined(RH_ASK_ARDUINO_USE_TIMER2)
|
|
prescaler = timerCalc(_speed, (uint8_t)-1, &nticks);
|
|
if (!prescaler)
|
|
return; // fault
|
|
// Use timer 2
|
|
TCCR2A = _BV(WGM21); // Turn on CTC mode)
|
|
// convert prescaler index to TCCRnB prescaler bits CS10, CS11, CS12
|
|
TCCR2B = prescaler;
|
|
|
|
// Caution: special procedures for setting 16 bit regs
|
|
// is handled by the compiler
|
|
OCR2A = nticks;
|
|
// Enable interrupt
|
|
#ifdef TIMSK2
|
|
// atmega168
|
|
TIMSK2 |= _BV(OCIE2A);
|
|
#else
|
|
// others
|
|
TIMSK |= _BV(OCIE2A);
|
|
#endif // TIMSK2
|
|
#else
|
|
// Use timer 1
|
|
prescaler = timerCalc(_speed, (uint16_t)-1, &nticks);
|
|
if (!prescaler)
|
|
return; // fault
|
|
TCCR1A = 0; // Output Compare pins disconnected
|
|
TCCR1B = _BV(WGM12); // Turn on CTC mode
|
|
|
|
// convert prescaler index to TCCRnB prescaler bits CS10, CS11, CS12
|
|
TCCR1B |= prescaler;
|
|
|
|
// Caution: special procedures for setting 16 bit regs
|
|
// is handled by the compiler
|
|
OCR1A = nticks;
|
|
// Enable interrupt
|
|
#ifdef TIMSK1
|
|
// atmega168
|
|
TIMSK1 |= _BV(OCIE1A);
|
|
#else
|
|
// others
|
|
TIMSK |= _BV(OCIE1A);
|
|
#endif // TIMSK1
|
|
#endif
|
|
#endif
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_STM32F2) // Photon
|
|
// Inspired by SparkIntervalTimer
|
|
// We use Timer 6
|
|
void TimerInterruptHandler(); // Forward declaration for interrupt handler
|
|
#define SYSCORECLOCK 60000000UL // Timer clock tree uses core clock / 2
|
|
TIM_TimeBaseInitTypeDef timerInitStructure;
|
|
NVIC_InitTypeDef nvicStructure;
|
|
TIM_TypeDef* TIMx;
|
|
uint32_t period = (1000000 / 8) / _speed; // In microseconds
|
|
uint16_t prescaler = (uint16_t)(SYSCORECLOCK / 1000000UL) - 1; //To get TIM counter clock = 1MHz
|
|
|
|
attachSystemInterrupt(SysInterrupt_TIM6_Update, TimerInterruptHandler);
|
|
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM6, ENABLE);
|
|
nvicStructure.NVIC_IRQChannel = TIM6_DAC_IRQn;
|
|
TIMx = TIM6;
|
|
nvicStructure.NVIC_IRQChannelPreemptionPriority = 10;
|
|
nvicStructure.NVIC_IRQChannelSubPriority = 1;
|
|
nvicStructure.NVIC_IRQChannelCmd = ENABLE;
|
|
NVIC_Init(&nvicStructure);
|
|
timerInitStructure.TIM_Prescaler = prescaler;
|
|
timerInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
|
|
timerInitStructure.TIM_Period = period;
|
|
timerInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
|
|
timerInitStructure.TIM_RepetitionCounter = 0;
|
|
|
|
TIM_TimeBaseInit(TIMx, &timerInitStructure);
|
|
TIM_ITConfig(TIMx, TIM_IT_Update, ENABLE);
|
|
TIM_Cmd(TIMx, ENABLE);
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_CHIPKIT_CORE)
|
|
// UsingChipKIT Core on Arduino IDE
|
|
uint32_t chipkit_timer_interrupt_handler(uint32_t currentTime); // Forward declaration
|
|
attachCoreTimerService(chipkit_timer_interrupt_handler);
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_UNO32)
|
|
// Under old MPIDE, which has been discontinued:
|
|
// ON Uno32 we use timer1
|
|
OpenTimer1(T1_ON | T1_PS_1_1 | T1_SOURCE_INT, (F_CPU / 8) / _speed);
|
|
ConfigIntTimer1(T1_INT_ON | T1_INT_PRIOR_1);
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_ESP8266)
|
|
void RH_INTERRUPT_ATTR esp8266_timer_interrupt_handler(); // Forward declaration
|
|
// The - 120 is a heuristic to correct for interrupt handling overheads
|
|
_timerIncrement = (clockCyclesPerMicrosecond() * 1000000 / 8 / _speed) - 120;
|
|
timer0_isr_init();
|
|
timer0_attachInterrupt(esp8266_timer_interrupt_handler);
|
|
timer0_write(ESP.getCycleCount() + _timerIncrement);
|
|
// timer0_write(ESP.getCycleCount() + 41660000);
|
|
#elif (RH_PLATFORM == RH_PLATFORM_ESP32)
|
|
void RH_INTERRUPT_ATTR esp32_timer_interrupt_handler(); // Forward declaration
|
|
#if ESP_ARDUINO_VERSION_MAJOR >= 3
|
|
// Sigh, this changed, apparently in version 3.
|
|
timer = timerBegin(_speed * 8);
|
|
timerAttachInterrupt(timer, &esp32_timer_interrupt_handler);
|
|
timerAlarm(timer, 1, true, 0);
|
|
#else
|
|
// Prior to version 3
|
|
timer = timerBegin(0, 80, true); // Alarm value will be in in us
|
|
timerAttachInterrupt(timer, &esp32_timer_interrupt_handler, true);
|
|
timerAlarmWrite(timer, 1000000 / _speed / 8, true);
|
|
timerAlarmEnable(timer);
|
|
#endif
|
|
#endif
|
|
|
|
}
|
|
|
|
void RH_INTERRUPT_ATTR RH_ASK::setModeIdle()
|
|
{
|
|
if (_mode != RHModeIdle)
|
|
{
|
|
// Disable the transmitter hardware
|
|
writePtt(LOW);
|
|
writeTx(LOW);
|
|
_mode = RHModeIdle;
|
|
}
|
|
}
|
|
|
|
void RH_INTERRUPT_ATTR RH_ASK::setModeRx()
|
|
{
|
|
if (_mode != RHModeRx)
|
|
{
|
|
// Disable the transmitter hardware
|
|
writePtt(LOW);
|
|
writeTx(LOW);
|
|
_mode = RHModeRx;
|
|
}
|
|
}
|
|
|
|
void RH_ASK::setModeTx()
|
|
{
|
|
if (_mode != RHModeTx)
|
|
{
|
|
// PRepare state varibles for a new transmission
|
|
_txIndex = 0;
|
|
_txBit = 0;
|
|
_txSample = 0;
|
|
|
|
// Enable the transmitter hardware
|
|
writePtt(HIGH);
|
|
|
|
_mode = RHModeTx;
|
|
}
|
|
}
|
|
|
|
// Call this often
|
|
bool RH_ASK::available()
|
|
{
|
|
if (_mode == RHModeTx)
|
|
return false;
|
|
setModeRx();
|
|
if (_rxBufFull)
|
|
{
|
|
validateRxBuf();
|
|
_rxBufFull= false;
|
|
}
|
|
return _rxBufValid;
|
|
}
|
|
|
|
bool RH_INTERRUPT_ATTR RH_ASK::recv(uint8_t* buf, uint8_t* len)
|
|
{
|
|
if (!available())
|
|
return false;
|
|
|
|
if (buf && len)
|
|
{
|
|
// Skip the length and 4 headers that are at the beginning of the rxBuf
|
|
// and drop the trailing 2 bytes of FCS
|
|
uint8_t message_len = _rxBufLen-RH_ASK_HEADER_LEN - 3;
|
|
if (*len > message_len)
|
|
*len = message_len;
|
|
memcpy(buf, _rxBuf+RH_ASK_HEADER_LEN+1, *len);
|
|
}
|
|
_rxBufValid = false; // Got the most recent message, delete it
|
|
// printBuffer("recv:", buf, *len);
|
|
return true;
|
|
}
|
|
|
|
// Caution: this may block
|
|
bool RH_ASK::send(const uint8_t* data, uint8_t len)
|
|
{
|
|
uint8_t i;
|
|
uint16_t index = 0;
|
|
uint16_t crc = 0xffff;
|
|
uint8_t *p = _txBuf + RH_ASK_PREAMBLE_LEN; // start of the message area
|
|
uint8_t count = len + 3 + RH_ASK_HEADER_LEN; // Added byte count and FCS and headers to get total number of bytes
|
|
|
|
if (len > RH_ASK_MAX_MESSAGE_LEN)
|
|
return false;
|
|
|
|
// Wait for transmitter to become available
|
|
waitPacketSent();
|
|
|
|
if (!waitCAD())
|
|
return false; // Check channel activity
|
|
|
|
// Encode the message length
|
|
crc = RHcrc_ccitt_update(crc, count);
|
|
p[index++] = symbols[count >> 4];
|
|
p[index++] = symbols[count & 0xf];
|
|
|
|
// Encode the headers
|
|
crc = RHcrc_ccitt_update(crc, _txHeaderTo);
|
|
p[index++] = symbols[_txHeaderTo >> 4];
|
|
p[index++] = symbols[_txHeaderTo & 0xf];
|
|
crc = RHcrc_ccitt_update(crc, _txHeaderFrom);
|
|
p[index++] = symbols[_txHeaderFrom >> 4];
|
|
p[index++] = symbols[_txHeaderFrom & 0xf];
|
|
crc = RHcrc_ccitt_update(crc, _txHeaderId);
|
|
p[index++] = symbols[_txHeaderId >> 4];
|
|
p[index++] = symbols[_txHeaderId & 0xf];
|
|
crc = RHcrc_ccitt_update(crc, _txHeaderFlags);
|
|
p[index++] = symbols[_txHeaderFlags >> 4];
|
|
p[index++] = symbols[_txHeaderFlags & 0xf];
|
|
|
|
// Encode the message into 6 bit symbols. Each byte is converted into
|
|
// 2 6-bit symbols, high nybble first, low nybble second
|
|
for (i = 0; i < len; i++)
|
|
{
|
|
crc = RHcrc_ccitt_update(crc, data[i]);
|
|
p[index++] = symbols[data[i] >> 4];
|
|
p[index++] = symbols[data[i] & 0xf];
|
|
}
|
|
|
|
// Append the fcs, 16 bits before encoding (4 6-bit symbols after encoding)
|
|
// Caution: VW expects the _ones_complement_ of the CCITT CRC-16 as the FCS
|
|
// VW sends FCS as low byte then hi byte
|
|
crc = ~crc;
|
|
p[index++] = symbols[(crc >> 4) & 0xf];
|
|
p[index++] = symbols[crc & 0xf];
|
|
p[index++] = symbols[(crc >> 12) & 0xf];
|
|
p[index++] = symbols[(crc >> 8) & 0xf];
|
|
|
|
// Total number of 6-bit symbols to send
|
|
_txBufLen = index + RH_ASK_PREAMBLE_LEN;
|
|
|
|
// Start the low level interrupt handler sending symbols
|
|
setModeTx();
|
|
|
|
return true;
|
|
}
|
|
|
|
// Read the RX data input pin, taking into account platform type and inversion.
|
|
bool RH_INTERRUPT_ATTR RH_ASK::readRx()
|
|
{
|
|
bool value;
|
|
#if (RH_PLATFORM == RH_PLATFORM_GENERIC_AVR8)
|
|
value = ((RH_ASK_RX_PORT & (1<<RH_ASK_RX_PIN)) ? 1 : 0);
|
|
#else
|
|
value = digitalRead(_rxPin);
|
|
#endif
|
|
return value ^ _rxInverted;
|
|
}
|
|
|
|
// Write the TX output pin, taking into account platform type.
|
|
void RH_INTERRUPT_ATTR RH_ASK::writeTx(bool value)
|
|
{
|
|
#if (RH_PLATFORM == RH_PLATFORM_GENERIC_AVR8)
|
|
((value) ? (RH_ASK_TX_PORT |= (1<<RH_ASK_TX_PIN)) : (RH_ASK_TX_PORT &= ~(1<<RH_ASK_TX_PIN)));
|
|
// No longer relevant: PinStatus onlty used in old versions
|
|
//#elif (RH_PLATFORM == RH_PLATFORM_ATTINY_MEGA)
|
|
// digitalWrite(_txPin, (PinStatus)value);
|
|
#else
|
|
digitalWrite(_txPin, value);
|
|
#endif
|
|
}
|
|
|
|
// Write the PTT output pin, taking into account platform type and inversion.
|
|
void RH_INTERRUPT_ATTR RH_ASK::writePtt(bool value)
|
|
{
|
|
#if (RH_PLATFORM == RH_PLATFORM_GENERIC_AVR8)
|
|
#if RH_ASK_PTT_PIN
|
|
((value) ? (RH_ASK_PTT_PORT |= (1<<RH_ASK_PTT_PIN)) : (RH_ASK_PTT_PORT &= ~(1<<RH_ASK_PTT_PIN)));
|
|
#else
|
|
((value) ? (RH_ASK_TX_PORT |= (1<<RH_ASK_TX_PIN)) : (RH_ASK_TX_PORT &= ~(1<<RH_ASK_TX_PIN)));
|
|
#endif
|
|
// This no longer relevant: ater version use uint8_t
|
|
//#elif (RH_PLATFORM == RH_PLATFORM_ATTINY_MEGA)
|
|
// digitalWrite(_txPin, (PinStatus)(value ^ _pttInverted));
|
|
#else
|
|
digitalWrite(_pttPin, value ^ _pttInverted);
|
|
#endif
|
|
}
|
|
|
|
uint8_t RH_ASK::maxMessageLength()
|
|
{
|
|
return RH_ASK_MAX_MESSAGE_LEN;
|
|
}
|
|
|
|
#if (RH_PLATFORM == RH_PLATFORM_ARDUINO)
|
|
// Assume Arduino Uno (328p or similar)
|
|
#if defined(RH_ASK_ARDUINO_USE_TIMER2)
|
|
#define RH_ASK_TIMER_VECTOR TIMER2_COMPA_vect
|
|
#else
|
|
#define RH_ASK_TIMER_VECTOR TIMER1_COMPA_vect
|
|
#endif
|
|
#elif (RH_PLATFORM == RH_PLATFORM_ATTINY)
|
|
#if defined(RH_ASK_ATTINY_USE_TIMER1)
|
|
#define RH_ASK_TIMER_VECTOR TIM1_COMPA_vect
|
|
#else
|
|
#define RH_ASK_TIMER_VECTOR TIM0_COMPA_vect
|
|
#endif //RH_ASK_ATTINY_USE_TIMER1
|
|
#elif (RH_PLATFORM == RH_PLATFORM_GENERIC_AVR8)
|
|
#define __COMB(a,b,c) (a##b##c)
|
|
#define _COMB(a,b,c) __COMB(a,b,c)
|
|
#define RH_ASK_TIMER_VECTOR _COMB(TIMER,RH_ASK_TIMER_INDEX,_COMPA_vect)
|
|
#endif
|
|
|
|
#if (RH_PLATFORM == RH_PLATFORM_ARDUINO) && defined(__arm__) && defined(CORE_TEENSY)
|
|
void TIMER1_COMPA_vect(void)
|
|
{
|
|
thisASKDriver->handleTimerInterrupt();
|
|
}
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_ARDUINO) && defined (__arm__) && defined(ARDUINO_ARCH_SAMD)
|
|
// Arduino Zero
|
|
void TC3_Handler()
|
|
{
|
|
// The type cast must fit with the selected timer mode
|
|
TcCount16* TC = (TcCount16*)RH_ASK_ZERO_TIMER; // get timer struct
|
|
TC->INTFLAG.bit.MC0 = 1;
|
|
thisASKDriver->handleTimerInterrupt();
|
|
}
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_ARDUINO) && defined(__arm__) && defined(ARDUINO_SAM_DUE)
|
|
// Arduino Due
|
|
void TC1_Handler()
|
|
{
|
|
TC_GetStatus(RH_ASK_DUE_TIMER, 1);
|
|
thisASKDriver->handleTimerInterrupt();
|
|
}
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_ARDUINO) && defined(ARDUINO_ARCH_RP2040)
|
|
void picoInterrupt()
|
|
{
|
|
hw_clear_bits(&timer_hw->intr, 1u << RH_ASK_PICO_ALARM_NUM);
|
|
set_pico_alarm(thisASKDriver->speed());
|
|
thisASKDriver->handleTimerInterrupt();
|
|
}
|
|
|
|
#elif defined(BOARD_NAME)
|
|
// ST's Arduino Core STM32, https://github.com/stm32duino/Arduino_Core_STM32
|
|
// Declaration of the callback function changed in 1.9
|
|
#if (STM32_CORE_VERSION >= 0x01090000)
|
|
// This really should be callback_function_t interrupt() but some platform compilers
|
|
// warn/error, thinking there should be a return value
|
|
void interrupt()
|
|
#else
|
|
void interrupt(HardwareTimer*)
|
|
#endif
|
|
{
|
|
thisASKDriver->handleTimerInterrupt();
|
|
}
|
|
#elif (RH_PLATFORM == RH_PLATFORM_ARDUINO) && (defined(ARDUINO_ARCH_STM32) || defined(ARDUINO_ARCH_STM32F1) || defined(ARDUINO_ARCH_STM32F3) || defined(ARDUINO_ARCH_STM32F4) || defined(ARDUINO_ARCH_RP2040))
|
|
// Roger Clark Arduino STM32, https://github.com/rogerclarkmelbourne/Arduino_STM32
|
|
void interrupt()
|
|
{
|
|
thisASKDriver->handleTimerInterrupt();
|
|
}
|
|
|
|
#elif defined(ARDUINO_UNOR4_MINIMA) || defined(ARDUINO_UNOR4_WIFI)
|
|
// callback method used by timer
|
|
void timer_callback(timer_callback_args_t __attribute((unused)) *p_args)
|
|
{
|
|
thisASKDriver->handleTimerInterrupt();
|
|
}
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_ARDUINO) && defined(RH_CUBE_CELL_BOARD)
|
|
// Cube cell interrupt
|
|
void timer_callback(void)
|
|
{
|
|
TimerStart(&timer);
|
|
thisASKDriver->handleTimerInterrupt();
|
|
}
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_ARDUINO) || (RH_PLATFORM == RH_PLATFORM_GENERIC_AVR8) || (RH_PLATFORM == RH_PLATFORM_ATTINY)
|
|
// This is the interrupt service routine called when timer1 overflows
|
|
// Its job is to output the next bit from the transmitter (every 8 calls)
|
|
// and to call the PLL code if the receiver is enabled
|
|
//ISR(SIG_OUTPUT_COMPARE1A)
|
|
ISR(RH_ASK_TIMER_VECTOR)
|
|
{
|
|
thisASKDriver->handleTimerInterrupt();
|
|
}
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_MSP430) || (RH_PLATFORM == RH_PLATFORM_STM32)
|
|
// LaunchPad, Maple
|
|
void interrupt()
|
|
{
|
|
thisASKDriver->handleTimerInterrupt();
|
|
}
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_STM32F2) // Photon
|
|
void TimerInterruptHandler()
|
|
{
|
|
thisASKDriver->handleTimerInterrupt();
|
|
}
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_MSP430)
|
|
interrupt(TIMER0_A0_VECTOR) Timer_A_int(void)
|
|
{
|
|
thisASKDriver->handleTimerInterrupt();
|
|
};
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_CHIPKIT_CORE)
|
|
// Using ChipKIT Core on Arduino IDE
|
|
uint32_t chipkit_timer_interrupt_handler(uint32_t currentTime)
|
|
{
|
|
thisASKDriver->handleTimerInterrupt();
|
|
return (currentTime + ((CORE_TICK_RATE * 1000)/8)/thisASKDriver->speed());
|
|
}
|
|
|
|
#elif (RH_PLATFORM == RH_PLATFORM_UNO32)
|
|
// Under old MPIDE, which has been discontinued:
|
|
extern "C"
|
|
{
|
|
void __ISR(_TIMER_1_VECTOR, ipl1) timerInterrupt(void)
|
|
{
|
|
thisASKDriver->handleTimerInterrupt();
|
|
mT1ClearIntFlag(); // Clear timer 1 interrupt flag
|
|
}
|
|
}
|
|
#elif (RH_PLATFORM == RH_PLATFORM_ESP8266)
|
|
void RH_INTERRUPT_ATTR esp8266_timer_interrupt_handler()
|
|
{
|
|
// timer0_write(ESP.getCycleCount() + 41660000);
|
|
// timer0_write(ESP.getCycleCount() + (clockCyclesPerMicrosecond() * 100) - 120 );
|
|
timer0_write(ESP.getCycleCount() + thisASKDriver->_timerIncrement);
|
|
// static int toggle = 0;
|
|
// toggle = (toggle == 1) ? 0 : 1;
|
|
// digitalWrite(4, toggle);
|
|
thisASKDriver->handleTimerInterrupt();
|
|
}
|
|
#elif (RH_PLATFORM == RH_PLATFORM_ESP32)
|
|
void RH_INTERRUPT_ATTR esp32_timer_interrupt_handler()
|
|
{
|
|
thisASKDriver->handleTimerInterrupt();
|
|
}
|
|
#elif (RH_PLATFORM == RH_PLATFORM_ATTINY_MEGA)
|
|
ISR(RH_ATTINY_MEGA_ASK_TIMER_VECTOR)
|
|
{
|
|
thisASKDriver->handleTimerInterrupt();
|
|
RH_ATTINY_MEGA_ASK_TIMER.INTFLAGS = TCB_CAPT_bm;
|
|
}
|
|
#endif
|
|
|
|
// Convert a 6 bit encoded symbol into its 4 bit decoded equivalent
|
|
uint8_t RH_INTERRUPT_ATTR RH_ASK::symbol_6to4(uint8_t symbol)
|
|
{
|
|
uint8_t i;
|
|
uint8_t count;
|
|
|
|
// Linear search :-( Could have a 64 byte reverse lookup table?
|
|
// There is a little speedup here courtesy Ralph Doncaster:
|
|
// The shortcut works because bit 5 of the symbol is 1 for the last 8
|
|
// symbols, and it is 0 for the first 8.
|
|
// So we only have to search half the table
|
|
for (i = (symbol>>2) & 8, count=8; count-- ; i++)
|
|
if (symbol == symbols[i]) return i;
|
|
|
|
return 0; // Not found
|
|
}
|
|
|
|
// Check whether the latest received message is complete and uncorrupted
|
|
// We should always check the FCS at user level, not interrupt level
|
|
// since it is slow
|
|
void RH_ASK::validateRxBuf()
|
|
{
|
|
uint16_t crc = 0xffff;
|
|
// The CRC covers the byte count, headers and user data
|
|
for (uint8_t i = 0; i < _rxBufLen; i++)
|
|
crc = RHcrc_ccitt_update(crc, _rxBuf[i]);
|
|
if (crc != 0xf0b8) // CRC when buffer and expected CRC are CRC'd
|
|
{
|
|
// Reject and drop the message
|
|
_rxBad++;
|
|
_rxBufValid = false;
|
|
return;
|
|
}
|
|
|
|
// Extract the 4 headers that follow the message length
|
|
_rxHeaderTo = _rxBuf[1];
|
|
_rxHeaderFrom = _rxBuf[2];
|
|
_rxHeaderId = _rxBuf[3];
|
|
_rxHeaderFlags = _rxBuf[4];
|
|
if (_promiscuous ||
|
|
_rxHeaderTo == _thisAddress ||
|
|
_rxHeaderTo == RH_BROADCAST_ADDRESS)
|
|
{
|
|
_rxGood++;
|
|
_rxBufValid = true;
|
|
}
|
|
}
|
|
|
|
void RH_INTERRUPT_ATTR RH_ASK::receiveTimer()
|
|
{
|
|
bool rxSample = readRx();
|
|
|
|
// Integrate each sample
|
|
if (rxSample)
|
|
_rxIntegrator++;
|
|
|
|
if (rxSample != _rxLastSample)
|
|
{
|
|
// Transition, advance if ramp > 80, retard if < 80
|
|
_rxPllRamp += ((_rxPllRamp < RH_ASK_RAMP_TRANSITION)
|
|
? RH_ASK_RAMP_INC_RETARD
|
|
: RH_ASK_RAMP_INC_ADVANCE);
|
|
_rxLastSample = rxSample;
|
|
}
|
|
else
|
|
{
|
|
// No transition
|
|
// Advance ramp by standard 20 (== 160/8 samples)
|
|
_rxPllRamp += RH_ASK_RAMP_INC;
|
|
}
|
|
if (_rxPllRamp >= RH_ASK_RX_RAMP_LEN)
|
|
{
|
|
// Add this to the 12th bit of _rxBits, LSB first
|
|
// The last 12 bits are kept
|
|
_rxBits >>= 1;
|
|
|
|
// Check the integrator to see how many samples in this cycle were high.
|
|
// If < 5 out of 8, then its declared a 0 bit, else a 1;
|
|
if (_rxIntegrator >= 5)
|
|
_rxBits |= 0x800;
|
|
|
|
_rxPllRamp -= RH_ASK_RX_RAMP_LEN;
|
|
_rxIntegrator = 0; // Clear the integral for the next cycle
|
|
|
|
if (_rxActive)
|
|
{
|
|
// We have the start symbol and now we are collecting message bits,
|
|
// 6 per symbol, each which has to be decoded to 4 bits
|
|
if (++_rxBitCount >= 12)
|
|
{
|
|
// Have 12 bits of encoded message == 1 byte encoded
|
|
// Decode as 2 lots of 6 bits into 2 lots of 4 bits
|
|
// The 6 lsbits are the high nybble
|
|
uint8_t this_byte =
|
|
(symbol_6to4(_rxBits & 0x3f)) << 4
|
|
| symbol_6to4(_rxBits >> 6);
|
|
|
|
// The first decoded byte is the byte count of the following message
|
|
// the count includes the byte count and the 2 trailing FCS bytes
|
|
// REVISIT: may also include the ACK flag at 0x40
|
|
if (_rxBufLen == 0)
|
|
{
|
|
// The first byte is the byte count
|
|
// Check it for sensibility. It cant be less than 7, since it
|
|
// includes the byte count itself, the 4 byte header and the 2 byte FCS
|
|
_rxCount = this_byte;
|
|
if (_rxCount < 7 || _rxCount > RH_ASK_MAX_PAYLOAD_LEN)
|
|
{
|
|
// Stupid message length, drop the whole thing
|
|
_rxActive = false;
|
|
_rxBad++;
|
|
return;
|
|
}
|
|
}
|
|
_rxBuf[_rxBufLen++] = this_byte;
|
|
|
|
if (_rxBufLen >= _rxCount)
|
|
{
|
|
// Got all the bytes now
|
|
_rxActive = false;
|
|
_rxBufFull = true;
|
|
setModeIdle();
|
|
}
|
|
_rxBitCount = 0;
|
|
}
|
|
}
|
|
// Not in a message, see if we have a start symbol
|
|
else if (_rxBits == RH_ASK_START_SYMBOL)
|
|
{
|
|
// Have start symbol, start collecting message
|
|
_rxActive = true;
|
|
_rxBitCount = 0;
|
|
_rxBufLen = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
void RH_INTERRUPT_ATTR RH_ASK::transmitTimer()
|
|
{
|
|
if (_txSample++ == 0)
|
|
{
|
|
// Send next bit
|
|
// Symbols are sent LSB first
|
|
// Finished sending the whole message? (after waiting one bit period
|
|
// since the last bit)
|
|
if (_txIndex >= _txBufLen)
|
|
{
|
|
setModeIdle();
|
|
_txGood++;
|
|
}
|
|
else
|
|
{
|
|
writeTx(_txBuf[_txIndex] & (1 << _txBit++));
|
|
if (_txBit >= 6)
|
|
{
|
|
_txBit = 0;
|
|
_txIndex++;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (_txSample > 7)
|
|
_txSample = 0;
|
|
}
|
|
|
|
void RH_INTERRUPT_ATTR RH_ASK::handleTimerInterrupt()
|
|
{
|
|
if (_mode == RHModeRx)
|
|
receiveTimer(); // Receiving
|
|
else if (_mode == RHModeTx)
|
|
transmitTimer(); // Transmitting
|
|
}
|
|
|
|
#endif //_SAMD51__
|