Using the CAN interface « LeafLabs Garden

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Using the CAN interface

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Started 4 years ago by tmbomber
Latest reply from Phono

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priusfan
Member

Bonjour,
I just ordered an olimexino stm32 and I am planning to install a dev I made on an mbed.
the app works well on mbed (NXP LPC1768), but I would prefer to use the olimexino because of the formfactor, because the can_transceiver is already there, and the lower power.
this app reads a parm file on SDcard
to select filters to apply,
to select requests to send,
also, it writes logs on this sdcard.
it communicates using a BT module rn42 @115200bps
it communicates to a Serial LCD @38400
it sends & analyse around 110 requests / sec on hybrid cars (prius).
it analyses a few filtered passive messages.

Using STM32, I understood the number of filters is 14 (512 on NXP), I understood I will loose USB when using CAN...

As I am a total newbie with mapple, could you, please, tell me if what I am planning to do is possible and how to start.
I join a link with the actual source for mbed. http://priusfan.info/canmonitor/mbed/CAN_hsd_bt_0050.zip

Thx

Posted 3 years ago #
dsgamermike
Member

Has anybody gotten x893's code to work? I can compile it and load it, but I can not get any data off of the canbus. I have it dumping everything to uart 1.

Posted 3 years ago #
Phono
Member

Same for me : I am a beginner with Olimexino and Maple environment. I tried X893's code, but I cannot have it send or read anything even by changing the mode to CAN_MODE_NORMAL. Besides this, I do not understand the example : what is the difference between read and recv? Between while(!canBus.available())
and
if (r_msg != NULL)
?
Currently I test one line at a time, and the line
mbx = canBus.send(&msg);
freezes the program when inserted in loop(). I would appreciate some kind of a user manual on this package.

Posted 3 years ago #
Phono
Member

Hi, does anyone know of a newsgroup where Maple/Olimex users meet? Or a web forum?

Posted 3 years ago #
x893
Member

I use CAN with STM32 for communicate with car (i not use Maple now). Also i update MapleCAN library on my site for Maple 12 version. But you need make a changes in Maple core to support CAN (maple dev not make this changes last 1 year). Aslo i recommend you use any debugger (ST-Link, J-Link, ULink) to test CAN application because it really reduce development time. For check real communication protocol i use Microchip CAN analyzer.

Posted 3 years ago #
Phono
Member

Thank you, but could you add for example comments in your example, stating what every function call does, and why you use one rather than another, at this very place? It would help me.
So far, I have tested the code with the olimexino board connected to a CAN bus where a CAN analyser watches every traffic. I have changed "LOOPBACK" to "NORMAL" in the CANbus.begin call, and when the olimexino board starts, the CAN analyser shows garbage on the bus for a few milliseconds, then the bus goes on normally; but I never see the message in the example (ID=0x55, data = 0xAA, 0x55) go on the bus.
In addition, I have put extra code to make the LED blink. After the call to CANbus.send, the board freezes.
Do you have code where you just listen to the frames that pass on the bus and maybe print them out through a serial port?

Posted 3 years ago #
x893
Member

0. Update 3 core files
rcc.c
rcc.h
usb.c
1. You need install CAN terminator 120om on both sides.
2. I not use Maple and havn't any examples
3. All sources published so you can easy add any serial print.
4. Display mbx from code
mbx = canBus.send(&msg);

P.S. Use F205 MCU to reduce CAN/USB problem :)
P.P.S
Also try use poll mode
canBus.set_irq_mode(); // use irq mode
to
canBus.set_pool_mode();
this disable receiver irq

Posted 3 years ago #

Phono
Member

I think I found a bug in the package. In file "HardwareCAN.cpp", line 17, I changed as follows :

CAN_STATUS HardwareCAN::begin(CAN_SPEED speed, uint32 mode)
{
/* Begin Fix JMD ******************************************************
	if (can_init(Port, CAN_MCR_NART, CAN_SPEED_250) == CAN_OK)
*/
	if (can_init(Port, CAN_MCR_NART, Speed) == CAN_OK)
// End Fix JMD *******************************************************
		return can_set_mode(Port, mode);
	return can_status();
}

As it appears, the parameter Speed was not taken into account in the original version. I changed it so that it is passed to can_init().

However, having changed, I am still unable to receive frames from an active can bus, where I monitor the traffic.
I initialised as follows :

void setup()
{
  SerialUSB.end();  // Disable USB !!!

  canBus.map(CAN_GPIO_PB8_PB9);
  canBus.begin(CAN_SPEED_125, CAN_MODE_NORMAL);
  canBus.filter(0, 0, 0);
  canBus.set_pool_mode();
//  canBus.set_irq_mode();	// use irq mode

  msg.IDE = CAN_ID_STD;
  msg.RTR = CAN_RTR_DATA;
  msg.ID = 0x55;
  msg.DLC = 8;
  msg.Data[0] = 0x0;
  msg.Data[1] = 0x0;
  msg.Data[2] = 0x0;
  msg.Data[3] = 0x0;
  msg.Data[4] = 0x0;
  msg.Data[5] = 0x0;
  msg.Data[6] = 0x0;
  msg.Data[7] = 0x0;
}

void loop()
{
  r_msg = canBus.recv();
  if (r_msg != NULL)
  {
    canBus.free();
    // Here I actually blink a LED which initialization is not shown above for sake of clarity
  }
}

The LED is never blinked. Did I miss something in the initialization? Is the filter initialisation OK to receive any identifier?
I tested in poll mode and in interrupt mode, but none work.

Posted 3 years ago #

pvh
Member

X893, where can we find your latest hardwareCAN library for MAPLE IDE. After compiling your “bxCAN” example I get the following error:
************
C:\Users\PvH\Downloads\maple-ide-0.0.12-windowsxp32\maple-ide-0.0.12-windowsxp32\libraries\HardwareCAN\utility\can.c: In function 'can_deinit':
C:\Users\PvH\Downloads\maple-ide-0.0.12-windowsxp32\maple-ide-0.0.12-windowsxp32\libraries\HardwareCAN\utility\can.c:141: error: 'RCC_CAN' undeclared (first use in this function)
C:\Users\PvH\Downloads\maple-ide-0.0.12-windowsxp32\maple-ide-0.0.12-windowsxp32\libraries\HardwareCAN\utility\can.c:141: error: (Each undeclared identifier is reported only once
C:\Users\PvH\Downloads\maple-ide-0.0.12-windowsxp32\maple-ide-0.0.12-windowsxp32\libraries\HardwareCAN\utility\can.c:141: error: for each function it appears in.)
C:\Users\PvH\Downloads\maple-ide-0.0.12-windowsxp32\maple-ide-0.0.12-windowsxp32\libraries\HardwareCAN\utility\can.c: In function 'can_init':
************

Thanks!

Posted 3 years ago #
x893
Member

http://akb77.com/g/stm32/maplehardwarecan/

Posted 3 years ago #
pvh
Member

Thanks X893, I successfully compiled and transferred the example (bxCAN) to the Olimex STM32 with Maple.

I have used the example in your package to start with, but until now I do not have any results sending/receiving CAN messages from the Olimex STM32. I have changed the mode to "CAN_MODE_NORMAL", but also no results. The Olimex STM CAN interface is connected to a CANbus monitor device (2x 120 resistors, 2 meter cable in between).

Does anyone has an idea what’s going wrong?

Posted 3 years ago #
x893
Member

Hi pvh,
easy way - connect 2 olimex boards (change program on first to send data and second only receive and display), so you remove invalid timing.
Also you can change timing constants - after experiments with car ECU at 500kbits i change timing constants to next values

[CAN_SPEED_500] = { .btr = (
(( 3-1) << CAN_BTR_SJW_POS) |
((12-1) << CAN_BTR_TS1_POS) |
(( 5-1) << CAN_BTR_TS2_POS) |
(CAN_CLOCK / 500000UL - 1)
)},

can you print first 5 canBus.send(...) results ?
all .send return correct mailbox number (0-2) ?

Posted 3 years ago #
Phono
Member
Hi X893,
Hi all,

I finally could have the CAN work on my Olimexino board. There were a few bugs in the library I had to fix.
Please x893 note the following changes and if you can, amend the code on your repository.

1) In USB.C, anywhere, add :
```
//  Begin Fix JMD
void USB_HP_CAN_TX_IRQHandler (void);

void __irq_usb_hp_can_tx(void)
{
  USB_HP_CAN_TX_IRQHandler () ;
}
//  End Fix JMD
```
This is the interrupt handler for the CAN TX interrupt, which was missing.

Please note that this change produces errors in sketches that do not use the CAN library. X893, could you devise a way to correct this? For example using #ifdef...#endif blocks ?

2) in HardwareCAN.cpp
change method HardwareCAN::begin as follows :
```
CAN_STATUS HardwareCAN::begin(CAN_SPEED speed, uint32 mode)
{
/*  Begin Fix JMD
	if (can_init(Port, CAN_MCR_NART, CAN_SPEED_250) == CAN_OK)
 */
	if (can_init(Port, CAN_MCR_NART, speed) == CAN_OK)
 // End Fix JMD
		return can_set_mode(Port, mode);
	return can_status();
}
```
This allows to choose the bit rate, that was fixed to 250k.
Posted 3 years ago #
pvh
Member

Hello,
@ Phone: I did a quick check; the fixes worked out for me as well.
Message data 0xAA, 0x55 showed up in my CAN monitoring GUI.
The only message was only send once, is it also possible to send it cyclic?

@ X893: you are right, it is quit hard to debug Maple code/libraries without debugger or print output. Which development environment do you recommend in combination with a ARM-USB-TINY-H debugger?

Posted 3 years ago #
x893
Member

i use DIY j-link pro only.
Also i have ulink and coocox but i prefer j-link.
Keil as IDE (but for edit complex project better Visual Studio).

Posted 3 years ago #

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