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.
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
Hi @Alexis_A ,
thank you for your help.
This is my code:
FlexCan.h -> Define nodeB as the receiver
FlexCAN.c
/*
* Copyright (c) 2014 - 2016, Freescale Semiconductor, Inc.
* Copyright (c) 2016 - 2018, NXP.
* All rights reserved.
*
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* 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
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*
* 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.
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* 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.
I have a question:
If I want to receive more IDs, how can I do?
Thanks
Best regards,
Paola
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
In the Main Function:
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
