canReceive using a fix mailbox number (do not use CAN_ANY_MAILBOX)

[aurelien23]

Posted on July 10, 2014 at 14:34

Hello,

I want to use canReceive and specify the mailbox to read (do not use CAN_ANY_MAILBOX). Example: if I want to check the first mailbox, I use:

canReceive(can1.

canp

, 1, &rxmsg, TIME_IMMEDIATE) == MSG_OK

canReceive first checks if the buffer received data using the can_lld_is_rx_nonempty function. If you give the mailbox number 1 to this function, it checks the mailbox 0 (BUF[0]).

The problem is that next to this check, the function can_lld_receive will access the second mailbox (BUF[1]).

To fix this, I suggest to define CAN_ANY_MAILBOX to 0xFF and change the switch values in can_lld_is_rx_nonempty from 1-8 to 0-7.

My target is SPC56EL60 but it applies to all families and I use SPC5 Studio.

Is it a bug or I missed something? I can't update SPC5 Studio at the moment, this bug is maybe already fixed.

EDIT: using CAN_ANY_MAILBOX make these 2 functions searching through all mailboxes. In my example they both found that the first mailbox contains data, so it works... All the examples I found are using  CAN_ANY_MAILBOX, did anybody tried to specify a mailbox number?

[Erwan YVIN]

Posted on July 10, 2014 at 16:58

Hello Aurelien ,

Yes .. you have right

there is an issue when we set in a specific mailbox id :

from can_lld. part (can_lld_receive function):

  if(mailbox != CAN_ANY_MAILBOX) {

    mbid = mailbox;

  }

we should have :

  if(mailbox != CAN_ANY_MAILBOX) {

    mbid = mailbox-1;

  }

you can update manually :

c:\SPC5Studio\eclipse\plugins\org.chibios.spc5.components.hal.platform.spc56elxx_1.0.0.xxxxxxxx\component\lib\src\can_lld.c

the correction will be available in the next updated version in spc5-hal component (can low level driver)

   Best Regards

         Erwan

[aurelien23]

Posted on July 16, 2014 at 15:01

Hello,

it sounds logic to do so but it doesn't work. In debug on SPC56EL60 the function

can_lld_is_rx_nonempty always returns false and I can't explain why! If I use CAN_ANY_MAILBOX it works... And I verified that each mailbox scans (for loops) were finding the mailbox number I passed (to replace CAN_ANY_MAILBOX).

And this solution doesn't allow to read the mailbox BUF[0] since CAN_ANY_MAILBOX is defined as 0... It's why I suggested to define it to 0xFF and change the switch cases 1-8 to 0-7 in

can_lld_is_rx_nonempty.

Aurélien

[Erwan YVIN]

Posted on July 16, 2014 at 18:04

 Hello Aurelien ,

1) When we transmit into MailboxID 1 .. 

in can_lld_is_rx_nonempty ... if canReceive (MailboxId=1), we are waiting for  BUF[0]

BUT The data is received in BUF[1].

2)  When we transmit into MailboxID 2 .. 

in can_lld_is_rx_nonempty ... if canReceive (MailboxId=2), we are waiting for  BUF[1]

BUT The data is received in BUF[1].

your suggestion is good ;)

We are working on this issue and deliver a patch as soon as possible.

     Best regards

                         Erwan

[Erwan YVIN]

Posted on July 17, 2014 at 14:51

Hello Aurélien ,

we can not set CAN_ANY_MAILBOX to 0xFF because this constant is used for others devices (STM32 and so on ..).

in API level, the mailbox id should be between 1 and 8.

the mailboxid for the reception depends on the EID used.

our message has :txmsg.EID = 0x01234567;

the CAN settings for OS-Less CAN application is (cf screenshot):

Filter 0 Settings ==> Mailbox ID 1 (EID=0)

Filter 1 Settings ==> Mailbox ID 2 (EID=0x01234567)

Filter 2 Settings ==> Mailbox ID 3(EID=0)

Filter 3 Settings ==> Mailbox ID 4 (EID=0)

Filter 4 Settings ==> Mailbox ID 5 (EID=0)

Filter 5 Settings ==> Mailbox ID 6 (EID=0)

Filter 6 Settings ==> Mailbox ID 7 (EID=0)

Filter 7 Settings ==> Mailbox ID 8 (EID=0)

it means that if you transmit for a defined mailbox id :

canTransmit(&CAND1,

1 to 8, &txmsg, TIME_IMMEDIATE)

you should receive the message in mailbox id 2 (EID comparison) (cf Filter Settings):

canReceive(can1.canp,

2, &rxmsg, TIME_IMMEDIATE) == MSG_OK

the patch provided is working.

It will be available in the official update site.

i hope that i am clear.

Best regards

Erwan

________________

Attachments :

2014-07-17_144842.png : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006qWCb&d=%2Fa%2F0X0000000bo6%2FtBiD2ADDpYHHZ0TI3N2QHqCMzrb15BpXdaFTTe28fH8&asPdf=false

[Erwan YVIN]

Posted on July 18, 2014 at 16:12

Hello Aurélien ,

Official update site has been updated.

it contains :

#280836 can low level driver : Mailbox id issue in can_lld_receive

#266463

Add Chibios Components / Test Applications for SPC56ECxx family              Best regards

                             Erwan

[aurelien23]

Posted on July 22, 2014 at 11:19

Hello Erwan,

I updated to org.chibios.spc5.components.hal.platform.spc56elxx_1.0.0.201407151616 and still it doesn't work when I use a mailbox number. In canReceive, the call of

can_lld_receive is never reached. I configured mailboxes 1 to 3 and I successfully read their content when using CAN_ANY_MAILBOX. But when mentionning 1, 2 or 3, canReceive never return MSG_OK... I'm not in loopback mode. I send CAN frames using a PCAN interface.

Can anyone confirm that it works?

Regards,

Aurélien

[Erwan YVIN]

Posted on July 22, 2014 at 11:41

Hello Aurelien ,

By using the default configuration ,

and the patch, it is working well (cf Code Below)

EID 0x1234567

while (TRUE) {

/*

* Sends the TX CAN Message.

*/

if (CANtransReq == 1) {

if (canTransmit(&CAND1,

1, &txmsg, TIME_IMMEDIATE) != MSG_TIMEOUT) {

palTogglePad(PORT_D, PD_LED2);

CANtransReq = 0;

}

}

/*

* Receives the RX CAN Message.

*/

if (canReceive(can1.canp,

2

, &rxmsg, TIME_IMMEDIATE) == MSG_OK) {

/* Process message.*/

palTogglePad(PORT_D, can1.led);

}

}

return 0;

Write in BUF[1] (Cf Screenshot)

Could you send me your application by email or forum ?

Check your EID ''matching'' in Filter Settings ?

Best Regards

Erwan

________________

Attachments :

2014-07-22_114001.png : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006qWUp&d=%2Fa%2F0X0000000boL%2FlL1cPFGXSMdi2tnGCmBYA0mvjjhoIHJ_qUJbfwFjh8s&asPdf=false