TMS570LS1114: Which Register can set ACK filed ?

Qiu chi

Expert 1210 points

Part Number: TMS570LS1114

Hello,

Could you tell me how to set the ACK filed bytes in the DCAN? I want to know which rigister?

Best and Regard

Qiuchi

over 7 years ago

0 QJ Wang over 7 years ago

TI__Guru**** 197706 points

The ACK field is two bits long and consists of the acknowledge bit and an acknowledge delimiter bit.

If there are 3 nodes for example. node 1 transmits something and monitors the bus for a dominant bit in the ACK slot. Nodes 2 and 3 receive the message at the same time. If node 2 or 3 receive the message correctly, it will overwrite the ACK bit and make it dominant. There is no register to write the ACK manually.

0 Qiu chi over 7 years ago in reply to QJ Wang

Expert 1210 points

Dear QJ,
Thank you.
Best and Regard
Qiuchi

0 Qiu chi over 7 years ago in reply to QJ Wang

Expert 1210 points

But where is the ACK bit?How to find in the datasheet SPNU515B?

0 Qiu chi over 7 years ago in reply to QJ Wang

Expert 1210 points

In fact,I just want to know whereto find the ACK bit in the datasheet.

0 QJ Wang over 7 years ago in reply to Qiu chi

TI__Guru**** 197706 points

The ACK/NCK is transmitted automatically by the CAN receiver. This bit is not defined in any register, but you can see it from the CAN bus.

0 Qiu chi over 7 years ago in reply to QJ Wang

Expert 1210 points

How to see it from the CAN BUS?

0 QJ Wang over 7 years ago in reply to Qiu chi

TI__Guru**** 197706 points

The ACK FIELD is two bits long and contains the ACK SLOT and the ACK DELIMITER. In the ACK FIELD the transmitting station sends two ’recessive’ bits. A RECEIVER which has received a valid message correctly, reports this to the TRANSMITTER by sending a ’dominant’ bit during the ACK SLOT (it sends ’ACK’).

0 Qiu chi over 7 years ago in reply to QJ Wang

Expert 1210 points

Dear QJ Wang:

There are still some issue bothering me about ACK bit.

From the Spnu515b, I do not sure if RxOK bit and TxOK is the ACK bit. So, I test the two bits.

Watch Expression display the value of “ES_TxOK_flag=0 “and “ES_RxOK_flag=0”.

I still have trouble to watch the bit. Is the picture from the spnu515b?Sorry for my poor knowledge.

Thanks and Regards

Qiuchi

0 QJ Wang over 7 years ago in reply to Qiu chi

TI__Guru**** 197706 points

Hi Qiuchi,

ES is the error and status register. RxOK and TxOK in ES register are set if the message has been successfully received or transmitted. They have nothing to do with ACK.

0 Qiu chi over 7 years ago in reply to QJ Wang

Expert 1210 points

5126.spnu515b.pdf

Dear QJ Wang

I wanna watch the TX/RX state,but still have not found the ACK bit in this datasheet”spnu515b”.Could you tell me where to find ACK register bit in the attachment named "spnu515b"? It is better to know which page in this datasheet. I do not know how to watch it from CAN Bus.

Not: the attachment is the spnu515b.

Thanks and Regards

Qiuchi

0 QJ Wang over 7 years ago in reply to Qiu chi

TI__Guru**** 197706 points

Hi QIuchi,

I told you there is no register and no bit for ACK. When the receiver gets the data successfully, it will send a dominant bit (ACK), otherwise, it will send a recessive bit (NCK).

0 Qiu chi over 7 years ago in reply to QJ Wang

Expert 1210 points

Dear QJ Wang,

Thank you.I know.

Thanks and Regards

Qiuchi

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TMS570LS1114: Which Register can set ACK filed ?