Teensy 4.0 / High Voltage Heater

Looking at the schematics of the SK Pang board, I noticed that the CS pin of the MCP2004 LIN Transceiver is connected to Teensy pad 32. Pad 32 is on the bottom of the Teensy 4.0 PCB [left-bottom corner].

1707593484476.png


Can you actually see a physical wire or pogo-pin from that Teensy pad to the SK Pang board?

Paul
 
It appears so. I pulled the teensy off the board to snap these photos. I assume it was pushed together enough, but I reattached with a little more pressure to push but it will not go in all the way. Some pin is showing.
 

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I have continuity with the multi-meter from pin 32 to breakout board at both 3.3V pins and on the MCP2004 Chip, I am getting continuity on one of the pins. Either LIN_TXD or LIN_FAULT. Cannot tell which, but here is a photo. Pin that is pinging is the one on the bottom row second from the right.
 

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OK, thanks for the pictures - I just wanted to make sure CS is making it to the LIN transceiver. Now I understand why the Teensy 4.0 is included in the product.

Now back to your code. Studying the example https://github.com/MarkusLange/Teensy_3.x_4.x_and_LC_LIN_Master/blob/master/examples/NCV7430_Get_Full_Status/NCV7430_Get_Full_Status.ino
I would like to suggest the following minimal code:
C++:
#include "lin_bus.h"

LIN lin(&Serial3, 19200);

int lin_cs = 32;
uint8_t data[8];

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(lin_cs, OUTPUT);
  digitalWrite(lin_cs, HIGH);
}

void loop() {
  lin.order(24, 0, 0);
  Serial.println(lin.response(24, data, 8), HEX);
  digitalToggle(LED_BUILTIN);
  delay(100);
}

The only purpose is to read & display the measurement registers as basic as possible. If that works we can add writing the power register and plotting the data.

Paul

PS: the link to the LIN interface on the WIKI page seems not active
 
I have continuity with the multi-meter from pin 32 to breakout board at both 3.3V pins and on the MCP2004 Chip, I am getting continuity on one of the pins. Either LIN_TXD or LIN_FAULT. Cannot tell which, but here is a photo. Pin that is pinging is the one on the bottom row second from the right.
That would pin FAULT.
Important is that pin 2 of the MCP2004 is HIGH when the code is active.

Paul

1707596888271.png
 
To verify whether data is actually outputted using my code, I hooked up the logic analyzer to pin TX3. It is:

DSView-240210-215406.png


Paul
 
Paul. When I compiled your code above, the board connects and disconnects and connects again every 10 seconds. Should it be doing that?
 
From the specification
Paul. When I compiled your code above, the board connects and disconnects and connects again every 10 seconds. Should it be doing that?
No, my code is not doing that.
But I may have found an important clue. In the Webasto LIN document you attached in message #32, I see this:

1707598924472.png


HVH shall be a LIN slave node following the LIN specification pacakge 2.1.
That means that we have to tell the library to calculate the Enhanced Checksum by adding the "lin2x" parameter.
Updated code:
C++:
#include "lin_bus.h"

LIN lin(&Serial3, 19200);

int lin_cs = 32;
uint8_t data[8];

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(lin_cs, OUTPUT);
  digitalWrite(lin_cs, HIGH);
}

void loop() {
  lin.order(24, 0, 0, lin2x);
  Serial.println(lin.response(24, data, 8, lin2x), HEX);
  digitalToggle(LED_BUILTIN);
  delay(100);
}

And the accompanying LA screenshot:

DSView-240210-220726.png


Paul
 
Without this analyzer, will I be able to see data output on the serial monitor or plotter?
Yes, you should. The LA is only reading the data on the TX3 line. If a had an actual LIN device, I probably would have seen the response data as well.

Paul
 
Pin 1 (RX) is reading 3.3V while code is running. Nothing from Pin 2.
Pin1 (RXD) reading HIGH is normal. Only during a LIN message (~5ms) it can go LOW. See LA screenshot.
But pin 2 of the MCP2004 should definitely be HIGH. pinMode(lin_cs, OUTPUT); digitalWrite(lin_cs, HIGH); drive Teensy pin 32 HIGH.

By the way, this 10s dis/reconnecting: does that happen with the Webasto device connected to the LIN bus? If so, what happens if you disconnect the Webasto device?

Paul
 
Paul, I know we were pulling things back, but when I included your lin2x into the longer code, the board stays connected with and without WEBASTO connected AND pin 2 is now showing 3.3V, so a good sign, no? I need to go test it in the garage now with the heater on.

Code:
#include "lin_bus.h"

// Create an IntervalTimer object
IntervalTimer myTimer;

int ledState = LOW;                // ledState used to set the LED
unsigned long interval = 200000;   // interval at which to blinkLED to run every 0.2 seconds
uint16_t Power = 175; // set to required power
uint8_t Temperature = 45; //set to required temperature
uint16_t tmpheater = 0;
uint16_t udcheater = 0;
uint16_t powerheater = 0;

LIN lin;

int lin_cs = 32; // cs and serial port set for skpang LIN / FDCAN board

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(lin_cs, OUTPUT);
  digitalWrite(lin_cs, HIGH);
 
  //Serial.begin(19200);
  //Serial.print("HVH50 Heater demo");
 
  myTimer.begin(blinkLED, interval);

  LIN l(&Serial3, 9600);
  //LIN l(&Serial3, 19200); /// Change to this for 19200 /////
  lin = l;
 
}

void loop() {
  // heater
  SendLin();
  delay(100); // wait 100ms
  //Serial.print(" Heater test\n");
}

void blinkLED() {
  ledState = !ledState;
 
  digitalWrite(LED_BUILTIN, ledState);
}

  static void SendLin()
{
   static bool read = true;
   uint8_t data[8];
  if (lin.response(22, data, 8, lin2x) >=0) // -1 indicates crc error, 9600
  //if (lin.response(24, data, 8, lin2x) >=0) /// Change to this for 19200 /////
     {
     tmpheater = data[1] - 40;
     udcheater = data[4] | (data[5] & 3) << 8;
     powerheater =((data[5] >> 2) | (data[6] << 8)) * 20;
     Serial.print("Temp:");
     Serial.print(tmpheater);
     Serial.print(",");
     Serial.print("Udc:");
     Serial.print(udcheater);
     Serial.print(",");
     Serial.print("Power:");
     Serial.println(powerheater);
     }
   if (read)
   {
      lin.order(22, 0, 0, lin2x); // 9600
      //lin.order(24, 0, 0, lin2x); /// Change to this for 19200 /////
   }
   else
   {
        uint8_t lindata[] = {uint8_t(Power/40), uint8_t(Temperature+40), 0, 8};
          lin.order(21, lindata, 4); // this for 9600
      //lin.order(35, lindata, 4); /// Change to this for 19200 /////
      //Serial.print("\n Sending power and temperature");
   }

   read = !read;
}
 
Paul, I know we were pulling things back, but when I included your lin2x into the longer code, the board stays connected with and without WEBASTO connected AND pin 2 is now showing 3.3V, so a good sign, no? I need to go test it in the garage now with the heater on.
Yeah, that's a good sign. Perhaps there should be some time between lin.order() and lin.response()?
I also saw that you reverted back to 9600bps?

Paul
 
still no hot water, but PINS 1,2 and 4 get 3.3v and board is staying connected. If I can find a way to work with your shorter code without the disconnection issue, that would be great. Thank you, by they way, for all of this great assistance and sleuthing.
 
Yeah, that's a good sign. Perhaps there should be some time between lin.order() and lin.response()?
I also saw that you reverted back to 9600bps?
I am floating between 9600 and 19200 because the OI guys found their webasto was at 9600 . . . so I try both every time . . . not sure if there is a way to sniff the baud rate with a simple program.
 
I'm wondering why we actually need the lin.order(24, 0, 0, lin2x);? ID24 is a read-register, so why do we need to write "0,0"?
Perhaps comment out lin.order(24, 0, 0, lin2x);? in your code?

Paul
 
Paul, once I added in the blink LED to your shorter code, it stopped disconnecting and I am getting the blinking amber light.

With the heater disconnected, I am getting this on the Serial Monitor: FFFFFFFF

1707603931223.png


Revised Code:

Code:
#include "lin_bus.h"
// Create an IntervalTimer object 
IntervalTimer myTimer;
int ledState = LOW;                // ledState used to set the LED
unsigned long interval = 200000;   // interval at which to blinkLED to run every 0.2 seconds
LIN lin;
int lin_cs = 32; // cs and serial port set for skpang LIN / FDCAN board
uint8_t data[8];
void blinkLED() {
  ledState = !ledState;
  
  digitalWrite(LED_BUILTIN, ledState);
}
void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(lin_cs, OUTPUT);
  digitalWrite(lin_cs, HIGH);
  
  myTimer.begin(blinkLED, interval);
  //LIN l(&Serial3, 9600);
  LIN l(&Serial3, 19200); /// Change to this for 19200 /////
  lin = l;
  
}
void loop() {
  lin.order(22, 0, 0, lin2x);
  Serial.println(lin.response(22, data, 8, lin2x), HEX);
  digitalToggle(LED_BUILTIN);
  delay(100);
}
 
Paul, once I added in the blink LED to your shorter code, it stopped disconnecting and I am getting the blinking amber light.
Weird, adding a timer that stops disconnecting...
With the heater disconnected, I am getting this on the Serial Monitor: FFFFFFFF
0xFFFFFFFF means that it is reading HIGH's only. HIGH is the default state of the DATA line. And 0xFFFFFFFF is only 4 bytes - you would expect lin.response(22, data, 8, lin2x to read 8 bytes.

It's close to midnight here, and my brains are quitting. Will be back tomorrow.

Paul
 
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