CAN comm Bit manupulation using S32k14x EAR SDK

[akhilranga]

Hi there,

Using the following syntax i could able to observe and monitor the CAN frame and it's Byte information.

I have build this CAN code using the S32k14x EAR SDK.  

can_message_t StdTxMsg23 = {
            	  .cs = 0U,
            	  .id = TX_MSG_ID_23,
             .data[0] = ExtRxMsg12.data[0],
		     .data[1] = ExtRxMsg12.data[1],
			 .data[2] = ExtRxMsg12.data[2],
			 .data[3] = ExtRxMsg12.data[3],
			 .data[4] = ExtRxMsg12.data[4],
			 .data[5] = ExtRxMsg12.data[5],
			 .data[6] = ExtRxMsg12.data[6],
			 .data[7] = ExtRxMsg12.data[7],
              .length = 8U
            	        };

But i would also like to monitor and manupulate at bit level in each of these bytes. So, can you please help me with syntax or something through which i can enable this manupulation. 

Ex : CAN FRAME 

ID: 0x301

Length: 8 Bytes

DATA : 0xFF 0x00 0x35 0x55 0x00 0xFF 0x89 0xCD

Byte 6 from the above frame is 0x89 when converted to binary it is 1000 1001 . 

So, in this frame i want to check whether the Bit 3 is 1 or 0 in this case it is 1 and if i want to change the Bit 2 to 1 or 0. How can i do this part. Please help me how can i do this level of monitoring and manupulation. 

[Senlent]

Hi@akhilranga

for example: 0x89

uint8_t Bit_3 = (0x89 >> 3) & 0x01;// read 0x89 bit3

uint8_t Bit_2 = 0x89 | (0x01 << 2);// set 0x89 bit2 to 1,10001101

uint8_t Bit_2 = 0x89 & (~(0x01 << 2));//set 0x89 bit2 to 0,10001001

[akhilranga]

Hi @Senlent 

But the 0x89 is not an ID of the frame and it is not static value. It is the value of a varying (hexadeceimal)  Byte 6  of the CAN Frame with ID 301.   S0, and if i try to manupulate the bit inside that byte 6 (0x89) then the value of that also changes. 

In my Example 

ExtRxMsg12.data[6] = 0x89 . So, my question was how can i manupulate the bit values in the ExtRxMsg12.data[6] which is mapped to the 0x301 ID can frame's Byte 6 indicator.

[Senlent · Accepted solution]

Hi@akhilranga

I don't quiet understand your question, there is no difference between my last reply.

.data[6] = (ExtRxMsg12.data[6] >> 3) & 0x01;// read 0x89 bit3

.data[6] = ExtRxMsg12.data[6] | (0x01 << 2);// set 0x89 bit2 to 1,10001101

.data[6] = ExtRxMsg12.data[6] & (~(0x01 << 2));//set 0x89 bit2 to 0,10001001

[akhilranga]

Hi @Senlent 

Sorry if i couldn't able to communicate my issue properly.

But the recent reply where you replaced the 0x89 with ExtRxMsg12.data[6]. This makes more sense to me.

What i was saying in the earlier message was that we can't use 0x89 as a Byte 6 indicator because it will be varrying and i thought it should be inidated with a proper Byte 6 assigned indicator which is ExtRxMsg12.data6. So with your latest reply i got the answer what i am looking for. So, i will try this approach and get back to you if i require any further support 

Thank You