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Added Teensy support. #28

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Added Teensy support. #28

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663daae
Added Teensy support. Only tested with Teensy 4.1
0Hogan Aug 22, 2022
7d6f255
Fixed bug where the IntervalTimer wasn't initiated
0Hogan Aug 25, 2022
f882754
Fixed a library issue encountered on a different computer.
0Hogan Sep 7, 2022
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78 changes: 42 additions & 36 deletions src/IBusBM.cpp
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Original file line number Diff line number Diff line change
@@ -1,32 +1,32 @@
/*
* Interface to the RC IBus protocol
*
*
* Based on original work from: https://gitlab.com/timwilkinson/FlySkyIBus
* Extended to also handle sensors/telemetry data to be sent back to the transmitter,
* interrupts driven and other features.
*
* This lib requires a hardware UART for communication
* Another version using software serial is here https://github.com/Hrastovc/iBUStelemetry
*
* Explaination of sensor/ telemetry prtocol here:
*
* Explanation of sensor/telemetry protocol here:
* https://github.com/betaflight/betaflight/wiki/Single-wire-FlySky-(IBus)-telemetry
*
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
*
* Created 12 March 2019 Bart Mellink
* Updated 4 April 2019 to support ESP32
* updated 13 jun 2019 to support STM32 (pauluzs)
* Updated 21 Jul 2020 to support MBED (David Peverley)
* Updated 21 Jul 2020 to support MBED (David Peverley)
*/

#include <Arduino.h>
#include "IBusBM.h"

// pointer to the first class instance to be used to call the loop() method from timer interrupt
// will be initiated by class constructor, then daisy channed to other class instances if we have more than one
// will be initiated by class constructor, then daisy chained to other class instances if we have more than one
IBusBM* IBusBMfirst = NULL;


Expand All @@ -46,7 +46,7 @@ void onTimer() {
#if defined(ARDUINO_ARCH_MBED)
extern "C" {
void TIMER4_IRQHandler_v() {
if (NRF_TIMER4->EVENTS_COMPARE[0] == 1) {
if (NRF_TIMER4->EVENTS_COMPARE[0] == 1) {
onTimer();
NRF_TIMER4->EVENTS_COMPARE[0] = 0;
}
Expand All @@ -58,11 +58,11 @@ extern "C" {
/*
* supports max 14 channels in this lib (with messagelength of 0x20 there is room for 14 channels)

Example set of bytes coming over the iBUS line for setting servos:
Example set of bytes coming over the iBUS line for setting servos:
20 40 DB 5 DC 5 54 5 DC 5 E8 3 D0 7 D2 5 E8 3 DC 5 DC 5 DC 5 DC 5 DC 5 DC 5 DA F3
Explanation
Protocol length: 20
Command code: 40
Command code: 40
Channel 0: DB 5 -> value 0x5DB
Channel 1: DC 5 -> value 0x5Dc
Channel 2: 54 5 -> value 0x554
Expand All @@ -83,6 +83,8 @@ extern "C" {

#if defined(_VARIANT_ARDUINO_STM32_)
void IBusBM::begin(HardwareSerial &serial, TIM_TypeDef * timerid, int8_t rxPin, int8_t txPin) {
#elif defined(TEENSY)
void IBusBM::begin(HardwareSerial &serial, IntervalTimer* timerid, int8_t rxPin, int8_t txPin) {
#else
void IBusBM::begin(HardwareSerial &serial, int8_t timerid, int8_t rxPin, int8_t txPin) {
#endif
Expand Down Expand Up @@ -111,9 +113,12 @@ void IBusBM::begin(HardwareSerial &serial, int8_t timerid, int8_t rxPin, int8_t
// on AVR architectures Timer0 is already used for millis() - we'll just interrupt somewhere in the middle and call the TIMER0_COMPA_vect interrupt
OCR0A = 0xAF;
TIMSK0 |= _BV(OCIE0A);
#elif defined(TEENSY)
timerid = new IntervalTimer;
timerid->begin(onTimer, 1000); // Execute onTimer() every 1000us (1ms)
#else
// on other architectures we need to use a time
#if defined(ARDUINO_ARCH_ESP32)
#if defined(ARDUINO_ARCH_ESP32)
hw_timer_t * timer = NULL;
timer = timerBegin(timerid, F_CPU / 1000000L, true); // defaults to timer_id = 0; divider=80 (1 ms); countUp = true;
timerAttachInterrupt(timer, &onTimer, true); // edge = true
Expand All @@ -132,42 +137,44 @@ void IBusBM::begin(HardwareSerial &serial, int8_t timerid, int8_t rxPin, int8_t
NRF_TIMER2->TASKS_CLEAR = 1; // clear the task first to be usable for later

// Set prescaler & compare register.
// Prescaler = 0 gives 16MHz timer.
// Prescaler = 4 (2^4) gives 1MHz timer.
NRF_TIMER4->PRESCALER = 4 << TIMER_PRESCALER_PRESCALER_Pos;
NRF_TIMER4->CC[0] = 1000;
// Prescaler = 0 gives 16MHz timer.
// Prescaler = 4 (2^4) gives 1MHz timer.
NRF_TIMER4->PRESCALER = 4 << TIMER_PRESCALER_PRESCALER_Pos;
NRF_TIMER4->CC[0] = 1000;

// Enable interrupt on Timer 4 for CC[0] compare match events
NRF_TIMER4->INTENSET = TIMER_INTENSET_COMPARE0_Enabled << TIMER_INTENSET_COMPARE0_Pos;
NRF_TIMER4->SHORTS = TIMER_SHORTS_COMPARE0_CLEAR_Enabled << TIMER_SHORTS_COMPARE0_CLEAR_Pos;

NVIC_EnableIRQ(TIMER4_IRQn);

NRF_TIMER4->TASKS_START = 1; // Start TIMER2


#else
// It should not be too difficult to support additional architectures as most have timer functions, but I only tested AVR and ESP32
#warning "Timing only supportted for AVR, ESP32 and STM32 architectures. Use timerid IBUSBM_NOTIMER"
#warning "Timing only supported for AVR, ESP32, and STM32 architectures. Use timerid IBUSBM_NOTIMER"
#endif
#endif
}
IBusBMfirst = this;
IBusBMfirst = this;
}

// called from timer interrupt or mannually by user (if IBUSBM_NOTIMER set in begin())
void IBusBM::loop(void) {

// if we have multiple instances of IBusBM, we (recursively) call the other instances loop() function
if (IBusBMnext) IBusBMnext->loop();
if (IBusBMnext) IBusBMnext->loop();

// only process data already in our UART receive buffer
// only process data already in our UART receive buffer
while (stream->available() > 0) {
// only consider a new data package if we have not heard anything for >3ms
uint32_t now = millis();
if (now - last >= PROTOCOL_TIMEGAP){
state = GET_LENGTH;
}
last = now;

uint8_t v = stream->read();
switch (state) {
case GET_LENGTH:
Expand All @@ -188,7 +195,7 @@ void IBusBM::loop(void) {
state = GET_CHKSUML;
}
break;

case GET_CHKSUML:
lchksum = v;
state = GET_CHKSUMH;
Expand All @@ -197,7 +204,7 @@ void IBusBM::loop(void) {
case GET_CHKSUMH:
// Validate checksum
if (chksum == (v << 8) + lchksum) {
// Checksum is all fine Execute command -
// Checksum is all fine Execute command -
uint8_t adr = buffer[0] & 0x0f;
if (buffer[0]==PROTOCOL_COMMAND40) {
// Valid servo command received - extract channel data
Expand All @@ -215,14 +222,14 @@ void IBusBM::loop(void) {
delayMicroseconds(100);
switch (buffer[0] & 0x0f0) {
case PROTOCOL_COMMAND_DISCOVER: // 0x80, discover sensor
cnt_poll++;
// echo discover command: 0x04, 0x81, 0x7A, 0xFF
cnt_poll++;
// echo discover command: 0x04, 0x81, 0x7A, 0xFF
stream->write(0x04);
stream->write(PROTOCOL_COMMAND_DISCOVER + adr);
chksum = 0xFFFF - (0x04 + PROTOCOL_COMMAND_DISCOVER + adr);
break;
case PROTOCOL_COMMAND_TYPE: // 0x90, send sensor type
// echo sensortype command: 0x06 0x91 0x00 0x02 0x66 0xFF
// echo sensortype command: 0x06 0x91 0x00 0x02 0x66 0xFF
stream->write(0x06);
stream->write(PROTOCOL_COMMAND_TYPE + adr);
stream->write(s->sensorType);
Expand All @@ -232,20 +239,20 @@ void IBusBM::loop(void) {
case PROTOCOL_COMMAND_VALUE: // 0xA0, send sensor data
cnt_sensor++;
uint8_t t;
// echo sensor value command: 0x06 0x91 0x00 0x02 0x66 0xFF
// echo sensor value command: 0x06 0x91 0x00 0x02 0x66 0xFF
stream->write(t = 0x04 + s->sensorLength);
chksum = 0xFFFF - t;
stream->write(t = PROTOCOL_COMMAND_VALUE + adr);
chksum -= t;
stream->write(t = s->sensorValue & 0x0ff);
chksum -= t;
stream->write(t = (s->sensorValue >> 8) & 0x0ff);
stream->write(t = (s->sensorValue >> 8) & 0x0ff);
chksum -= t;
if (s->sensorLength==4) {
stream->write(t = (s->sensorValue >> 16) & 0x0ff);
stream->write(t = (s->sensorValue >> 16) & 0x0ff);
chksum -= t;
stream->write(t = (s->sensorValue >> 24) & 0x0ff);
chksum -= t;
stream->write(t = (s->sensorValue >> 24) & 0x0ff);
chksum -= t;
}
break;
default:
Expand All @@ -254,7 +261,7 @@ void IBusBM::loop(void) {
}
if (adr>0) {
stream->write(chksum & 0x0ff);
stream->write(chksum >> 8);
stream->write(chksum >> 8);
}
}
}
Expand Down Expand Up @@ -293,4 +300,3 @@ void IBusBM::setSensorMeasurement(uint8_t adr, int32_t value) {
if (adr<=NumberSensors && adr>0)
sensors[adr-1].sensorValue = value;
}

35 changes: 24 additions & 11 deletions src/IBusBM.h
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,11 +1,11 @@
/*
* Interface to the RC IBus protocol
*
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
*
* Created 12 March 2019 Bart Mellink
*/
#ifndef IBusBM_h
Expand All @@ -16,8 +16,15 @@
#if defined(ARDUINO_ARCH_MBED)
#include "mbed.h"
#include "HardwareSerial.h"

// Teensy: 3.0 || 3.1/3.2 || 3.5 || 3.6 || LC || 4.0 (Beta) || 4.1
#elif defined(__MK20DX128__) || defined(__MK20DX256__) || defined(__MK64FX512__) || defined(__MK66FX1M0__) || defined(__MKL26Z64__) || defined(__IMXRT1052__) || defined(__IMXRT1062__)
#define TEENSY
#include "IntervalTimer.h"
#include "HardwareSerial.h"
#endif


// if you have an opentx transciever you can add additional sensor types here.
// see https://github.com/cleanflight/cleanflight/blob/7cd417959b3cb605aa574fc8c0f16759943527ef/src/main/telemetry/ibus_shared.h
// below the values supported by the Turnigy FS-MT6 transceiver
Expand All @@ -29,10 +36,11 @@
#define IBUS_SERVO 0xfd // Servo value



#if defined(ARDUINO_ARCH_MBED)
#define HardwareSerial arduino::HardwareSerial
#else
#if !defined(ARDUINO_ARCH_MEGAAVR)
#if !defined(ARDUINO_ARCH_MEGAAVR) && !defined(TEENSY)
class HardwareSerial;
#endif
#endif
Expand All @@ -41,26 +49,31 @@ class Stream;
class IBusBM {

public:
#if defined(_VARIANT_ARDUINO_STM32_)
#if defined(_VARIANT_ARDUINO_STM32_) && !defined(TEENSY)
#if !defined(STM32_CORE_VERSION) || (STM32_CORE_VERSION < 0x01090000)
#error "Due to API change, this sketch is compatible with STM32_CORE_VERSION >= 0x01090000"
#endif
#define IBUSBM_NOTIMER NULL // no timer interrupt used
void begin(HardwareSerial &serial, TIM_TypeDef * timerid=TIM1, int8_t rxPin=-1, int8_t txPin=-1);
#else
#define IBUSBM_NOTIMER -1 // no timer interrupt used
void begin(HardwareSerial &serial, int8_t timerid=0, int8_t rxPin=-1, int8_t txPin=-1);
#if defined(TEENSY)
#define IBUSBM_NOTIMER -1 // Timer interrupt is used.
void begin(HardwareSerial &serial, IntervalTimer* timerid, int8_t rxPin=-1, int8_t txPin=-1);
#else
#define IBUSBM_NOTIMER -1 // no timer interrupt used
void begin(HardwareSerial &serial, int8_t timerid=0, int8_t rxPin=-1, int8_t txPin=-1);
#endif
#endif
uint16_t readChannel(uint8_t channelNr); // read servo channel 0..9
uint8_t addSensor(uint8_t type, uint8_t len=2); // add sensor type and data length (2 or 4), returns address
void setSensorMeasurement(uint8_t adr, int32_t value);

void loop(void); // used internally for interrupt handline, but needs to be defined as public

volatile uint8_t cnt_poll; // count received number of sensor poll messages
volatile uint8_t cnt_sensor; // count times a sensor value has been sent back
volatile uint8_t cnt_rec; // count received number of servo messages

private:
enum State {GET_LENGTH, GET_DATA, GET_CHKSUML, GET_CHKSUMH, DISCARD};

Expand All @@ -73,7 +86,7 @@ class IBusBM {
static const uint8_t PROTOCOL_COMMAND_TYPE = 0x90; // Command discover sensor (lowest 4 bits are sensor)
static const uint8_t PROTOCOL_COMMAND_VALUE = 0xA0; // Command send sensor data (lowest 4 bits are sensor)
static const uint8_t SENSORMAX = 10; // Max number of sensors

uint8_t state; // state machine state for iBUS protocol
HardwareSerial *stream; // serial port
uint32_t last; // milis() of prior message
Expand Down