ESP32 port tx/rx for sbus2 about sbus2-telemetry

[BrushlessPower]

Dear magnum,

sorry for the late reply, i was out of office for 2 weeks.

please look in "SBUS_usart_ESP32.cpp"

the is a define for the Pins. You can use almost every pin you want.

actual it's pin 25 and 26
#define SBUS2_UART_RX_PIN (GPIO_NUM_25)
#define SBUS2_UART_TX_PIN (GPIO_NUM_26)

you will need a 1k resistor between rx and tx. Connect the SBUS2 Cable to RX.

Keep in mind that this version is not very stable and could have a lot of bugs. That's the reason why i didn't write a "how to"

keep me up to Date

[magnum3131]

Hi thanks a lot,

I found the information by parsing your code, i use a 2.4K resistor and it works.
Unfortunately i have stability issue. When i try to implement GPS with TinyGPS++ i have frequently the following error.

Guru Meditation Error: Core 1 panic'ed (Interrupt wdt timeout on CPU1)
Core 1 register dump:
PC : 0x40081089 PS : 0x00060434 A0 : 0x40085168 A1 : 0x3ffbe7b0
A2 : 0xe000c000 A3 : 0x3ffc03c4 A4 : 0x3ff50000 A5 : 0x3ffc0441
A6 : 0x00000000 A7 : 0x00000019 A8 : 0x80081078 A9 : 0x3ffbe790
A10 : 0x00008000 A11 : 0x00000001 A12 : 0x00000000 A13 : 0x00000000
A14 : 0x3ffbeee0 A15 : 0x00000000 SAR : 0x00000011 EXCCAUSE: 0x00000006
EXCVADDR: 0x00000000 LBEG : 0x00000000 LEND : 0x00000000 LCOUNT : 0x00000000
Core 1 was running in ISR context:
EPC1 : 0x40081068 EPC2 : 0x00000000 EPC3 : 0x00000000 EPC4 : 0x40081089

Backtrace: 0x40081089:0x3ffbe7b0 0x40085165:0x3ffbe7d0 0x40081065:0x3ffbc570 0x400d7853:0x3ffbc590 0x4008b26a:0x3ffbc5b0 0x40089ac9:0x3ffbc5d0

Core 0 register dump:
PC : 0x400f096e PS : 0x00060134 A0 : 0x800d7856 A1 : 0x3ffbbff0
A2 : 0x00000000 A3 : 0x00000001 A4 : 0x00000000 A5 : 0x00000001
A6 : 0x00060320 A7 : 0x00000000 A8 : 0x800d741e A9 : 0x3ffbbfc0
A10 : 0x00000000 A11 : 0x400858f0 A12 : 0x00060320 A13 : 0x3ffbb710
A14 : 0x3ff000e0 A15 : 0x00000001 SAR : 0x00000000 EXCCAUSE: 0x00000006
EXCVADDR: 0x00000000 LBEG : 0x00000000 LEND : 0x00000000 LCOUNT : 0x00000000

Backtrace: 0x400f096e:0x3ffbbff0 0x400d7853:0x3ffbc010 0x4008b26a:0x3ffbc030 0x40089ac9:0x3ffbc050

Rebooting...
ets Jun 8 2016 00:22:57

rst:0xc (SW_CPU_RESET),boot:0x17 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0018,len:4
load:0x3fff001c,len:1044
load:0x40078000,len:8896
load:0x40080400,len:5828
entry 0x400806ac

I try to find a solution

Thanks a lot for your work

[magnum3131]

Hi,

I think i found the origin of my problem.

I change the TX/RX port for the following
#define SBUS2_UART_RX_PIN (GPIO_NUM_17)
#define SBUS2_UART_TX_PIN (GPIO_NUM_16)

But in your code you use pin 16 for " trigger PIN for logic analyser " this pin is use in

• void disable_receiving()
• static void IRAM_ATTR ISR_transmit_frame(void *arg)

Can i use an other free port for the trigger Pin ?

Thanks
Julien

[BrushlessPower]

You can use another port or delete the code with Pin16

It's just for debugging. With that i can connect an oscilloscope or logic analyzer to show me the correct timings.
My code has many lines for that reason, but most of them are commented out.

Maybe there is a Problem with TinyGPS or the Softserial
Please keep me up to Date

[magnum3131]

Hi,

I do some more test, I have the problem with TinyGPS++ also in software or hardware serial 2.

According to the debugger the ESP32 crash here :
########
Error
########

Guru Meditation Error: Core 1 panic'ed (Interrupt wdt timeout on CPU1)
Core 1 register dump:
PC : 0x40085119 PS : 0x00050434 A0 : 0x4008105c A1 : 0x3ffbe7d0
A2 : 0x00000250 A3 : 0x3ffbc570 A4 : 0x000637ff A5 : 0x3ffbe7b0
A6 : 0x00000000 A7 : 0x3ffc03c4 A8 : 0x3ff50000 A9 : 0x3ffc0441
A10 : 0x00000000 A11 : 0x00000019 A12 : 0x800811be A13 : 0x3ffbe790
A14 : 0x00000004 A15 : 0x00000000 SAR : 0x0000001e EXCCAUSE: 0x00000006
EXCVADDR: 0x00000000 LBEG : 0x00000000 LEND : 0x00000000 LCOUNT : 0x00000000
Core 1 was running in ISR context:
EPC1 : 0x4008105c EPC2 : 0x00000000 EPC3 : 0x00000000 EPC4 : 0x40085119

Backtrace: 0x40085119:0x3ffbe7d0 0x40081059:0x3ffbc570 0x400d75bf:0x3ffbc590 0x4008b256:0x3ffbc5b0 0x40089ab5:0x3ffbc5d0

PC: 0x40085119
EXCVADDR: 0x00000000

Decoding stack results
0x40081059: ISR_transmit_frame(void) at C:\Users\Portable\Documents\Arduino\libraries\SBUS2\SBUS_usart_ESP32.cpp line 304* => delayMicroseconds(5);
0x400d75bf: esp_vApplicationIdleHook at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/esp32/freertos_hooks.c line 63
0x4008b256: prvIdleTask at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/freertos/tasks.c line 3382
0x40089ab5: vPortTaskWrapper at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/freertos/port.c line 143

it's always the same error, maybe the delay is in cause ?

Thanks

Julien

[BrushlessPower]

Hello Julien,

please delete the delayMicroseconds(5) from the code and check if it's working

Sbus telemetry should work without delay
Please keep me up to Date

[magnum3131]

Hi,

I do some more test and i also have crash if i use the adafruit BME280 library.

It can work for 5 minutes and after crash every 20s and working again for 5min

According to the debugger it's crashing here
0x40080ff9: ISR_transmit_frame(void*) at C:\Users\Portable\Documents\Arduino\libraries\SBUS2\SBUS_usart_ESP32.cpp line 288
uart_write_bytes(UART_NUM_1, buffer, SLOT_DATA_LENGTH);

I'll continue my test

Thanks

Julien

[BrushlessPower]

Dear Julien,

ISR_transmit_frame(void*) is an function called by the Timer Interrupt.
I think there is a crash if the timer interrupt and another interrupt are running at the same time.

But this is just an idea.
ther could be 1000 other problems.

is the sbus telemetry working without other hardware/libraries?
are the other libraries working without sbus telemetry?

[magnum3131]

Hi,

Every things is working fine separately, i'll try to debug by searching timer interrupt

Thanks a lot
Julien

[magnum3131]

Hi,

More test today, still crash when SBUS2 function call to send telemetry data

• uart_write_bytes(UART_NUM_1, buffer, SLOT_DATA_LENGTH);
• uart_flush(UART_NUM_1); in enable receiving

I remark some difference between ESP32 lib et 328P

ESP 32
void SBUS2_uart_setup()
{
uint32_t counter = 64000;
uint8_t response = 0xAA;

328p arduino
void SBUS2_uart_setup ()
{
uint32_t counter = 640000;
uint8_t response = 0x00;

noInterrupts();

Are these difference normal ?

Thanks
Julien

[BrushlessPower]

yes this is normal

a big problem with this code is the USART Receive interrupt:
on328P the interrupt was called with every SBUS Byte
onESP32 the interrupt is called after a timeout after the last received byte -> that means that the interrupt i called once with every sbus frame

But in some cases the interrupt was called permanent
This could trigger a system crash and maybe its your problem.

But you can only check it with oscilloscpoe or logic analyser.

Possible fixes:

• change timeout of USART Interrupt -> BrushlessPower/SBUS2-Telemetry-ESP32#1
• change input buffer -> BrushlessPower/SBUS2-Telemetry-ESP32#1
• set the interrupt functions to critical

Example:
void IRAM_ATTR onTime() {
portENTER_CRITICAL_ISR(&timerMux);
interrupts++;
portEXIT_CRITICAL_ISR(&timerMux);
}

[BrushlessPower]

or try to use a different Timer and/or different USART

[magnum3131]

Hi,

Thanks for your answer, i played with these value but it still crashing
uart_intr.rxfifo_full_thresh = 1;
uart_intr.rx_timeout_thresh = 10;

For the interrupt functions critical, i read article and i found an exemple in Jeti Exbus telemetry

void IRAM_ATTR _onTimer() {
	portENTER_CRITICAL_ISR(&_timerMux);
	timerAlarmDisable(_timer);
	_bTimerRunning = false;
	Esp32Serial.uartDetachTx();
	// digitalWrite(15, false);
	portEXIT_CRITICAL_ISR(&_timerMux);
}

size_t JetiExBusESP32Serial::write(const uint8_t *buffer, size_t size)
{
	if( !_bTimerRunning )
	{
		**portENTER_CRITICAL(&_timerMux);**
		// https://techtutorialsx.com/2017/10/07/esp32-arduino-timer-interrupts/
		**_timer = timerBegin(0, 160, true);               // timer 0, prescaler 160 --> 80MHz/160 = 0,5 MHz = 2us, count up
		timerAttachInterrupt(_timer, &_onTimer, true);   // attach handler, trigger on edge 
		timerAlarmWrite(_timer, 2000L, true);            // 2000 * 2us = 4ms, single shot
		timerAlarmEnable(_timer); // start**
		_bTimerRunning = true;
		m_pSerial->uartAttachTx();
		// digitalWrite(15, true);
		**portEXIT_CRITICAL(&_timerMux);**
	}
	return m_pSerial->write(buffer, size);
}

For being sure, if i try to do the same thing in SBUS2 ESP32, do i have to do it in these function
static void IRAM_ATTR ISR_transmit_frame(void *arg) ???

Sorry for all my question, i'm not a software developper

Thanks a lot
Julien

[BrushlessPower]

portENTER_CRITICAL_ISR should be in every ISR i think. But it seems that the timer ISR is the Problem. You should start there.

I'am also no Software Dev. And ESP32 with RTOS and DUAL is a kind of black magic for me.

Greetings John

[magnum3131]

Hi,

I don't manage to improve the stability, it's crashing all the time when i change parameter.

Do you use the SBUS2 Librabry with sensor like bme280 or GPS ?

Thanks
Julien

[BrushlessPower]

No
but someone else used it with a GPS Sensor without problems.

Could you send me your Project (INO file)?
Maybe i can see something

[BrushlessPower]

i had a look on TinyGPS++
this is just a "conversion" from Chars to Coordinates....so its the same like delay(x)

could you try to read GPS data with your Hardware Serial (another than the SBUS Hardwareserial!) and just insert some delay()
without TinyGPS++

this test could be easily repeated without GPS sensor, just with a stream of UART Data

[magnum3131]

No
but someone else used it with a GPS Sensor without problems.

Could you send me your Project (INO file)?
Maybe i can see something

Hi John,

Thanks for your help

Here the files
https://www.mab.asso.fr/Futaba_Telemetry.rar

Julien

[magnum3131]

i had a look on TinyGPS++
this is just a "conversion" from Chars to Coordinates....so its the same like delay(x)

could you try to read GPS data with your Hardware Serial (another than the SBUS Hardwareserial!) and just insert some delay()
without TinyGPS++

this test could be easily repeated without GPS sensor, just with a stream of UART Data

I'll try these this night

thanks a lot
Julien

[magnum3131]

Hi Jonh,

I made more test today, i unloaded all library (Tiny GPS, BME280,..) and i still having crash by reading GPS value with only serial.read() command on hardware serial.

Guru Meditation Error: Core  1 panic'ed (Interrupt wdt timeout on CPU1)
Core 1 register dump:
PC      : 0x40084914  PS      : 0x00050434  A0      : 0x40081010  A1      : 0x3ffbe7d0  
A2      : 0x00000000  A3      : 0x00000013  A4      : 0x3ffbe7e8  A5      : 0x3ffbe7b0  
A6      : 0x00000004  A7      : 0x00000000  A8      : 0x3ff50000  A9      : 0x3ffc023d  
A10     : 0x00000000  A11     : 0x00000019  A12     : 0x00000001  A13     : 0x3ffbe780  
A14     : 0x00000000  A15     : 0x00000101  SAR     : 0x0000001d  EXCCAUSE: 0x00000006  
EXCVADDR: 0x00000000  LBEG    : 0x00000000  LEND    : 0x00000000  LCOUNT  : 0x00000000  
Core 1 was running in ISR context:
EPC1    : 0x40081010  EPC2    : 0x00000000  EPC3    : 0x00000000  EPC4    : 0x40084914

Backtrace: 0x40084914:0x3ffbe7d0 0x4008100d:0x3ffbc570 0x400d4b33:0x3ffbc590 0x4008a7c2:0x3ffbc5b0 0x40089281:0x3ffbc5d0

Core 0 register dump:
PC      : 0x400ed8fa  PS      : 0x00060134  A0      : 0x800d4b36  A1      : 0x3ffbbff0  
A2      : 0x00000000  A3      : 0x00000001  A4      : 0x00000000  A5      : 0x00000001  
A6      : 0x00060120  A7      : 0x00000000  A8      : 0x800d46fe  A9      : 0x3ffbbfc0  
A10     : 0x00000000  A11     : 0x400850a8  A12     : 0x00060120  A13     : 0x3ffbb970  
A14     : 0x00000000  A15     : 0x3ffbbce0  SAR     : 0x00000000  EXCCAUSE: 0x00000006  
EXCVADDR: 0x00000000  LBEG    : 0x00000000  LEND    : 0x00000000  LCOUNT  : 0x00000000  

Backtrace: 0x400ed8fa:0x3ffbbff0 0x400d4b33:0x3ffbc010 0x4008a7c2:0x3ffbc030 0x40089281:0x3ffbc050

Thanks
Julien

[BrushlessPower]

That's "good". With a simple Serial Terminal i can send a stread of Data to simulate the Problem

could you send me your INO file?
maybe via email
[email protected]

[BrushlessPower]

so a little test today:

GPS Data (750 Byte) with 0.1s delay send with HTerm

no crash over 30min

here my loop:

void loop()
{
uint16_t uart_dropped_frame = 0;
bool transmision_dropt_frame = false;
bool failsave = false;

/* DO YOUR STUFF HERE */
/* Make sure you do not do any blocking calls in the loop, e.g. delay()!!! */
while(Serial.available()){
  Serial.write(Serial.read());
}
//delay(500);

if (SBUS_Ready())
{                                      // SBUS Frames available -> Ready for getting Servo Data
    channel = SBUS2_get_servo_data(5); // Channel = Servo Value of Channel 5
    
}

//Serial.println(channel);

if (SBUS2_Ready())
{                                                                                                                  // SBUS2 Frame available -> Ready for transmit Telemetry
    //digitalWrite(13, HIGH);                                                                                        // set pin D13 (LED ON) -> SBUS2 Frames OK
    SBUS2_get_status(&uart_dropped_frame, &transmision_dropt_frame, &failsave);                                    // Check SBUS(2) Status
    if((uart_dropped_frame != 0) ||(transmision_dropt_frame != 0) || (failsave != 0) ){
      Serial.print("UART dropped Frame: ");
      Serial.println(uart_dropped_frame);
      Serial.print("Transmission dropped Frame: ");
      Serial.println(transmision_dropt_frame);
      Serial.print("Failsave: ");
      Serial.println(failsave);
    }
    send_alarm_as_temp125(ERROR_SLOT, ((failsave * 1000) + (transmision_dropt_frame * 100) + uart_dropped_frame)); // Warning with over Temp at Error Slot

    send_temp125(TEMPRATURE_SLOT, (int16_t)(uint16_t)50);                                        // Temperature [°C]
    send_RPM(RPM_SLOT, (uint16_t)600);                                                 // RPM = 600-> rounding Error +/- 3 RPM
    send_s1678_current(CURRENT_SLOT, (uint16_t)2345, (uint16_t)15000, (uint16_t)1234); // Current = 23.45A, Capacity = 15000mAh, Voltage = 12.34V

    send_f1675_gps(GPS_SLOT, (uint16_t)50, (int16_t)1000, (int16_t)200, latitude, longitude); // Speed = 50km/h, Altitude = 1000m, Vario = 200m/s
}
else
{
    // digitalWrite(13, LOW); // set pin D13 (LED OFF) -> No SBUS2 Frames
}

} // End of Loop()

[BrushlessPower]

try to update your SBUS lib with this file

SBUS_usart_ESP32.zip

[magnum3131]

Hi John, Thanks a lot for your help I updated with your new library but it's still crashing /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/freertos/queue.c:1446 (xQueueGenericReceive)- assert failed!abort() was called at PC 0x4008975b on core 1 Backtrace: 0x4008d284:0x3ffbe6c0 0x4008d4b1:0x3ffbe6e0 0x4008975b:0x3ffbe700 0x400edc90:0x3ffbe740 0x400d19f1:0x3ffbe780 0x40081024:0x3ffbe7a0 0x400850d1:0x3ffbe7d0 0x4000bfed:0x3ffc3a30 0x4008ab65:0x3ffc3a40 0x4008a034:0x3ffc3a60 0x400d375c:0x3ffc3a90 0x400d3b65:0x3ffc3ac0 0x400d2e85:0x3ffc3ae0 0x400d2f3a:0x3ffc3b10 0x400d2f89:0x3ffc3b40 0x400d26b0:0x3ffc3b60 0x400d2920:0x3ffc3b90 0x400d15b2:0x3ffc3bb0 0x400d13bd:0x3ffc3c00 0x400d49b9:0x3ffc3db0 0x40089a35:0x3ffc3dd0 I have notice you add these section, i'll try to change some parameter     uart_intr_config_t uart_intr;    uart_intr.intr_enable_mask = UART_RXFIFO_FULL_INT_ENA_M                            | UART_RXFIFO_TOUT_INT_ENA_M/*                            | UART_FRM_ERR_INT_ENA_M                            | UART_RXFIFO_OVF_INT_ENA_M                            | UART_BRK_DET_INT_ENA_M                            | UART_PARITY_ERR_INT_ENA_M*/;    uart_intr.rxfifo_full_thresh = 25; //UART_FULL_THRESH_DEFAULT,  //120 default!! aghh! need receive 120 chars before we see them    uart_intr.rx_timeout_thresh = 10; //UART_TOUT_THRESH_DEFAULT,  //10 works well for my short messages I need send/receive    uart_intr.txfifo_empty_intr_thresh = 10; //UART_EMPTY_THRESH_DEFAULT    uart_intr_config(UART_NUM_1, &uart_intr); ThanksJulien Le mercredi 15 juillet 2020 à 17:13:51 UTC+2, BrushlessPower <[email protected]> a écrit : try to update your SBUS lib with this file SBUS_usart_ESP32.zip — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or unsubscribe.

[BrushlessPower]

Dear Julien,

you should not try to change these Parameters without oscilloscope or logic analyzer!
The old code had a bug that sometime the USART Interrupt was called all the time without break. I thought it could be the reason for your crashes.

I tested the GPS Stream but i had no crashes. Everything worked perfect. But the USART Interrupt Bug started.
So i fixed that.

But at this point i cant help you any more. I cant reproduce your fault. And i cant use your sketch because i don't have your library's.

So start to reproduce the error with my example. And please keep me up to date with your findings.
Greetings John

[magnum3131]

Hi John,Thanks a lot, I'll use your test code to try to reproduce the error . Sometimes it's working few minutes before crashing. Julien Le 16 juil. 2020 07:47, BrushlessPower <[email protected]> a écrit : Dear Julien, you should not try to change these Parameters without oscilloscope or logic analyzer! The old code had a bug that sometime the USART Interrupt was called all the time without break. I thought it could be the reason for your crashes. I tested the GPS Stream but i had no crashes. Everything worked perfect. But the USART Interrupt Bug started. So i fixed that. But at this point i cant help you any more. I cant reproduce your fault. And i cant use your sketch because i don't have your library's. So start to reproduce the error with my example. And please keep me up to date with your findings. Greetings John —You are receiving this because you authored the thread.Reply to this email directly, view it on GitHub, or unsubscribe.