Hi,
I modified the example "s32k144_Project_FlexCAN" for the s32k144 board to receive only the CAN Message with the ID 0X555. I wrote this code in the main function:
I want that every time the CAN message arrives, the s32k144 receives the CAN Message and the Red Led is turn on; in contrast, the Blue Led is turn on.
But when I debug my code I'm not able to see the switch between red and blue led.
How could I solve this problem?
In addition how it is possibile to print on the console the ID of CAN message? Finally how Could I modify the code in order to receive more IDs than one?
Thanks
Best regards,
Paola
Hi p_decesare,
Did you initialize the PTD0 and PTD15? The project only initialize the PT16 by default.
If you want to only receive CAN Message with the ID 0X555, you can direct #define NODE_B in FlexCAN.h.(The codes has configure check all ID bits and allow 0x555 by default.)
Once you receive the CAN Message with the ID 0X555, the ricevuto will be true.
The this condition will never be established: if (((CAN0->IFLAG1 >> 4) & 0) && ricevuto)
And the blue LED will never light.
Please try to debug:
for (;;)
{ /* Loop: if a msg is received, transmit a msg */
if ((CAN0->IFLAG1 >> 4)) { /* If CAN 0 MB 4 flag is set (received msg), read MB4 */
FLEXCAN0_receive_msg (); /* Read message */
PTD->PSOR |= 1<<0 | 1<<16;
PTD->PCOR |= 1<<15;
}
else{
PTD->PSOR |= 1<<15 | 1<<16;
PTD->PCOR |= 1<<0;
}
}
If you put a breakpoint PTD->PCOR |= 1<<15;, you will see the red LED light once. And then the codes will turn off red LED and light bule LED.
If you want to use print on the console the ID of CAN message, please refer the "S32K144_Project_LPUART".
The ID of CAN message(RxID) will be read in FLEXCAN0_receive_msg.
Best Regards,
Robin
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I want that every time the CAN message arrives, the s32k144 receives the CAN Message and the Red Led is turn on; in contrast, the Blue Led is turn on.Would you please let me know when you want this light Red LED trun off? If you want to turn off the Red LED immediately when no CAN Message arrive, then the time to keep the Red LED on may be too short.(You may need to observe the signal of the Red LED by using oscilloscope). Otherwise you need to add delay for it, so that you can see the Red LED Blink by eyes instead of oscilloscope when the CAN message arrive.
The condition CAN0->IFLAG1 >> 4) & 1 is true each successful transmission or reception. The FLEXCAN0_receive_msg will Clear CAN 0 MB 4 flag(make the CAN0->IFLAG1 >> 4) & 1 is false).
I am afraid the IFLAG1 does not meet your needs, because the reception has finished.
Best Regards,
Robin
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Hi Robin,
thank you for your help. For the transmission of CAN message I adopted the methodology that if the user wrote the character "a" on the console, so the CAN message is transmitted. The code that is on the s32k144 is just for the reception. So I want that just when I wrote "a" the red Led is turn on; in contrast the blue led is turn on.
Robin could I ask you some things about CAN that I didn't understand? In the function FlexCAN_receive_msg I don't understand how the variable RXCODE, RXID are stored. I don't understand what means 4*msg_buf_size + 0 or +1. I'm studying the chapter of CAN on RM but I have some difficulties.
Finally, if you could, can tell me how it is possible to read more IDs? In this case, I know that should implemented more message buffer. But for the fact that, I'm not able to comprehend very well how to store the ID, the DATA FIELD, can help me?
Thank you for your time
Best regards,
Paola
In the function FlexCAN_receive_msg I don't understand how the variable RXCODE, RXID are stored. I don't understand what means 4*msg_buf_size + 0 or +1.
how it is possible to read more IDs?For more IDs, please refer the answer in : FlexCan S32K142 Need "simple" CAN0 Filters / matching example
