How to modify the code of FLEXCAN_S32K144 just for the reception of CAN msg

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How to modify the code of FLEXCAN_S32K144 just for the reception of CAN msg

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Contributor III

Hi community,

I'm working with the example FLEXCAN_S32K144. I want to modify this code in order to obtain just the reception of CAN message. I modified also the baud rate because I want as the baud rate 50KSamples/seconds and not 500KSamples/seconds.
I made these changes: I want to read the CAN message from the Message Buffer 4.
main.JPGflexCAN0_receive.JPGflexCAN0_init.JPG

 

I commented the function of transmit because for my purpose I want only read the CAN-Message.
But with these changes, the code doesn't work.

Where do I wrong?
Thanks

Best regards,
Paola

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1 Solution
185 Views
NXP TechSupport
NXP TechSupport

Hello @p_decesare,

You can do this two different ways, you can implement more mailboxes to receive different messages, or you can also use the individual mask to filter the messages receive and accept more ID in the same mailbox, for more information about the individual mask check the RXIMR0 - RXIMR31 in the reference manual.

Also, I will suggest checking the RTM 4.0.0 and the S32DS (link), this SDK implements drivers that are easier to implement than using a bare-metal implementation.

Best Regards,

Alexis Andalon

View solution in original post

4 Replies
212 Views
NXP TechSupport
NXP TechSupport

Hello @p_decesare ,

I see that you're using the example code from the S32K Cookbook, in this example, bellow the last sentence you have in the initialization is the mailbox configuration for the reception. Did you comment this part or leave it as it is?

CAN0->RAMn[ 4*MSG_BUF_SIZE + 0] = 0x04000000; /* Msg Buf 4, word 0: Enable for reception 	*/
                                                /* EDL,BRS,ESI=0: CANFD not used 				*/
                                                /* CODE=4: MB set to RX inactive 				*/
                                                /* IDE=0: Standard ID 							*/
                                                /* SRR, RTR, TIME STAMP = 0: not applicable 	*/
#ifdef NODE_A                                   /* Node A receives msg with std ID 0x511 		*/
  CAN0->RAMn[ 4*MSG_BUF_SIZE + 1] = 0x14440000; /* Msg Buf 4, word 1: Standard ID = 0x111 		*/
#else                                           /* Node B to receive msg with std ID 0x555 	*/
  CAN0->RAMn[ 4*MSG_BUF_SIZE + 1] = 0x15540000; /* Msg Buf 4, word 1: Standard ID = 0x555 		*/
#endif
                                /* PRIO = 0: CANFD not used */
  CAN0->MCR = 0x0000001F;       /* Negate FlexCAN 1 halt state for 32 MBs */

  while ((CAN0->MCR && CAN_MCR_FRZACK_MASK) >> CAN_MCR_FRZACK_SHIFT)  {}
  /* Good practice: wait for FRZACK to clear (not in freeze mode) */

  while ((CAN0->MCR && CAN_MCR_NOTRDY_MASK) >> CAN_MCR_NOTRDY_SHIFT)  {}
  /* Good practice: wait for NOTRDY to clear (module ready) */

 

Best Regards,

Alexis Andalon

196 Views
Contributor III

Hi @Alexis_A ,

thank you for your help.
This is my code:

FlexCan.h -> Define nodeB as the receiver

p_decesare_0-1600674340060.png

FlexCAN.c

/*
* Copyright (c) 2014 - 2016, Freescale Semiconductor, Inc.
* Copyright (c) 2016 - 2018, NXP.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY NXP "AS IS" AND ANY EXPRESSED OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL NXP OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/

#include "device_registers.h" /* include peripheral declarations */
#include "FlexCAN.h"

uint32_t RxCODE; /*< Received message buffer code */
uint32_t RxID; /*< Received message ID */
uint32_t RxLENGTH; /*< Recieved message number of data bytes */
uint32_t RxDATA[2]; /*< Received message data (2 words) */
uint32_t RxTIMESTAMP; /*< Received message time */

void FLEXCAN0_init(void)
{
#define MSG_BUF_SIZE 4 /* Msg Buffer Size. (CAN 2.0AB: 2 hdr + 2 data= 4 words) */
uint32_t i=0;

PCC->PCCn[PCC_FlexCAN0_INDEX] |= PCC_PCCn_CGC_MASK; /* CGC=1: enable clock to FlexCAN0 */

CAN0->MCR |= CAN_MCR_MDIS_MASK; /* MDIS=1: Disable module before selecting clock */
CAN0->CTRL1 &= ~CAN_CTRL1_CLKSRC_MASK; /* CLKsrc=0: Clock Source = SOSCDIV2 */
CAN0->MCR &= ~CAN_MCR_MDIS_MASK; /* MDIS=0; Enable module config. (Sets FRZ, HALT) */

while (!((CAN0->MCR & CAN_MCR_FRZACK_MASK) >> CAN_MCR_FRZACK_SHIFT)) {}
/*!
* Good practice:
* ===================================================
* wait for FRZACK=1 on freeze mode entry/exit
*/

CAN0->CTRL1 = 0x00DB0006; //500Ksamples/second

for(i=0; i<128; i++ )
{ /* CAN0: clear 32 msg bufs x 4 words/msg buf = 128 words */
CAN0->RAMn[i] = 0; /* Clear msg buf word */
}
for(i=0; i<16; i++ )
{ /* In FRZ mode, init CAN0 16 msg buf filters */
CAN0->RXIMR[i] = 0xFFFFFFFF; /* Check all ID bits for incoming messages */
}
CAN0->RXMGMASK = 0x1FFFFFFF; /* Global acceptance mask: check all ID bits */
CAN0->RAMn[ 4*MSG_BUF_SIZE + 0] = 0x04000000; /* Msg Buf 4, word 0: Enable for reception */
/* EDL,BRS,ESI=0: CANFD not used */
/* CODE=4: MB set to RX inactive */
/* IDE=0: Standard ID */
/* SRR, RTR, TIME STAMP = 0: not applicable */
#ifdef NODE_A /* Node A receives msg with std ID 0x511, 0x14440000 */
CAN0->RAMn[ 4*MSG_BUF_SIZE + 1] = 0x14440000; /* Msg Buf 4, word 1: Standard ID = 0x111 */
#else /* Node B to receive msg with std ID 0x555 */
CAN0->RAMn[ 4*MSG_BUF_SIZE + 1] = 0x15540000; /* Msg Buf 4, word 1: Standard ID = 0x555 */
#endif
/* PRIO = 0: CANFD not used */
CAN0->MCR = 0x0000001F; /* Negate FlexCAN 1 halt state for 32 MBs */

while ((CAN0->MCR && CAN_MCR_FRZACK_MASK) >> CAN_MCR_FRZACK_SHIFT) {}
/* Good practice: wait for FRZACK to clear (not in freeze mode) */

while ((CAN0->MCR && CAN_MCR_NOTRDY_MASK) >> CAN_MCR_NOTRDY_SHIFT) {}
/* Good practice: wait for NOTRDY to clear (module ready) */
}

void FLEXCAN0_transmit_msg(void)
{
/*! Assumption:
* =================================
* Message buffer CODE is INACTIVE
*/
CAN0->IFLAG1 = 0x00000001; /* Clear CAN 0 MB 0 flag without clearing others*/

CAN0->RAMn[ 0*MSG_BUF_SIZE + 2] = 0xA5112233; /* MB0 word 2: data word 0 */
CAN0->RAMn[ 0*MSG_BUF_SIZE + 3] = 0x44556677; /* MB0 word 3: data word 1 */

#ifdef NODE_A
CAN0->RAMn[ 0*MSG_BUF_SIZE + 1] = 0x15540000; /* MB0 word 1: Tx msg with STD ID 0x555 */
//#else
//CAN0->RAMn[ 0*MSG_BUF_SIZE + 1] = 0x14440000; /* MB0 word 1: Tx msg with STD ID 0x511 */
#endif
CAN0->RAMn[ 0*MSG_BUF_SIZE + 0] = 0x0C400000 | 8 << CAN_WMBn_CS_DLC_SHIFT;
/* MB0 word 0: */
/* EDL,BRS,ESI=0: CANFD not used */
/* CODE=0xC: Activate msg buf to transmit */
/* IDE=0: Standard ID */
/* SRR=1 Tx frame (not req'd for std ID) */
/* RTR = 0: data, not remote tx request frame */
/* DLC = 8 bytes */
}

void FLEXCAN0_receive_msg(void)
{
/*! Receive msg from ID 0x555 using msg buffer 4
* =============================================
*/
uint8_t j;
uint32_t dummy;

RxCODE = (CAN0->RAMn[ 4*MSG_BUF_SIZE + 0] & 0x07000000) >> 24; /* Read CODE field */
RxID = (CAN0->RAMn[ 4*MSG_BUF_SIZE + 1] & CAN_WMBn_ID_ID_MASK) >> CAN_WMBn_ID_ID_SHIFT; /* Read ID */


RxLENGTH = (CAN0->RAMn[ 4*MSG_BUF_SIZE + 0] & CAN_WMBn_CS_DLC_MASK) >> CAN_WMBn_CS_DLC_SHIFT; /* Read Message Length */

for (j=0; j<2; j++)
{ /* Read two words of data (8 bytes) */
RxDATA[j] = CAN0->RAMn[ 4*MSG_BUF_SIZE + 2 + j];
}
//RxTIMESTAMP = (CAN0->RAMn[ 0*MSG_BUF_SIZE + 0] & 0x000FFFF);
dummy = CAN0->TIMER; /* Read TIMER to unlock message buffers */
CAN0->IFLAG1 = 0x00000010; /* Clear CAN 0 MB 4 flag without clearing others*/

}

I commented the line //RXTIMESTAMP in the function FLEXCAN_receive because in the Buffer 0 there isn't the implemention of Transmission of Msg.
I commented the line  //#else
//CAN0->RAMn[ 0*MSG_BUF_SIZE + 1] = 0x14440000; /* MB0 word 1: Tx msg with STD ID 0x511 */ in the function FLEXCAN_transmit because the node B must not transmit message but just receive the message.

 

Finally,

main.c -> where I configured the led blue, green and red.

p_decesare_2-1600674653044.png

I have a question:

If I want to receive more IDs, how can I do?
Thanks

Best regards,

Paola

0 Kudos
186 Views
NXP TechSupport
NXP TechSupport

Hello @p_decesare,

You can do this two different ways, you can implement more mailboxes to receive different messages, or you can also use the individual mask to filter the messages receive and accept more ID in the same mailbox, for more information about the individual mask check the RXIMR0 - RXIMR31 in the reference manual.

Also, I will suggest checking the RTM 4.0.0 and the S32DS (link), this SDK implements drivers that are easier to implement than using a bare-metal implementation.

Best Regards,

Alexis Andalon

View solution in original post

174 Views
Contributor III

Hi @Alexis_A ,

thank you for your help.
Finally the last question. For the reception of more IDs, I chose as the Message Buffer, 4, 5, 6, 7. The IDs that I want to receive are:

0xEE
0xFE
0x101
0x103

If you have time, could you tell me if I wrong something for the configuration? This is the C file FlexCAN.c

p_decesare_0-1600759521579.png

p_decesare_1-1600759604918.png

p_decesare_2-1600759662373.png

 

In the Main Function:

p_decesare_3-1600759715387.png

 

 

In the script FlexCAN.H I defined the Node B. I commented the function of transmission because I want to receive the messages.
I ask you what I could have missed in my code because it didn't perform very well.
Thanks for your time

Best regards,

Paola

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