DS90UB954-Q1: What happens if CRC Error occurs

Hello Christian,

The 954 sends the data over the backchannel to the 935 and error(s) may occur over the transmission line. The DS90UB935-Q1 monitors the status of the back channel link. If there is an error in the backchannel, the back channel CRC errors are reported in the CRC_ERR bit (Register 0x52[1]). The number of CRC errors are stored in the CRC error counters and reported in the CRC_ERR_CNT1 (Register 0x55) and CRC_ERR_CNT2 (Register 0x56) registers. The CRC error counters are reset by setting the CRC_ERR_CLR (Register 0x49[3]) to 1. There is no error handling implemented on the serializer. To improve the received signal quality, adaptive equalization (AEQ) is implemented on the deserializer. 

Hope this helps. 

Best Regards,

Shruti More

Hello Shruti,

thank you for your answer it is really useful for me but i got another question. So if I'm sending an I2C command through the deserialiser, fpd-link path and the serialiser to another IC, and there occurs one simple bit error for example, will the deserialiser stop this command or will it just send it on  to the IC and only sets the crc error flag?

Best Regards,

Christian Brey

Hi Christian, 

As far as I know, the 935 flags a CRC error when there is an error in the backchannel; I am not entirely sure if the deserializer automatically stops sending I2C commands if the 935 gets a CRC error. I will look into this and get back to you. 

Does the set up you are referring to look like this:  IC <-- 935 <--> 954 ?

Best Regards,

Shruti

the setup is like this: Slave <--> 935 <--> 954 <--> Master

Hello Christian,

So far I understand that you want information regarding the following: When the 935 detects an error on the backchannel, is there a way to tell the 954 to stop sending data over the backchannel because the 935 has detected a CRC error?

In the 935 there is a register (0x1E) that you can program to send an alarm to the DES when it encounters a CRC error:

Respectively, in the 954, there is a register (0x51) you can program to receive information about the CRC error alarm from the SER on the forward channel:

The 954 will get information about the backchannel via the forward channel.

Hope this helps. 

Best Regards,

Shruti More

Hello Shruti,

thanks a lot for your help but actually I was wondering about what the serialiser 935 will do with the received data if it recognises, that it's corrupt?

Best Regards

Christian