EMIFA nEMA_WE_DQM of C674x

In addition to the above question, I also want to know if connecting nEMA_WE_DQM[1:0]  to 16-bit device is a must to write/read 8-bit value to/from 16-bit device.

Best regards,
Tsutomu Furuse

Tsutomu – San,

Yes, you’re correct

Tsutomu – San said:

 

Q : In addition to the above question, I also want to know if connecting nEMA_WE_DQM[1:0]  to 16-bit device is a must to write/read 8-bit value to/from 16-bit device.

The DQM signals toggle depending on the size of the access and the size of the EMIF bus.  For example, if your EMIF bus is16-bits in size and you perform a 32-bit access. You will see two 16-bit accesses on the bus with both DQM pins asserted (low).  If your access is 8 bits, then DQM0 will go low if the LSB of the address is 1 or DQM1 will go low if the MSB is 1.  If your EMIF bus is 8-bit in size, then only DQM0 should toggle and it will toggle for every access.

Regards

Antony

Antony,

Thank you for your answer.

 If your access is 8 bits, then DQM0 will go low if the LSB of the address is 1 or DQM1 will go low if the MSB is 1.

I'm not clear the above statement.
If the "B" of "LSB" and "MSB" is "Bit", I can understand as following.

DQM0 will go low if the LSB of the logical address is 0.
DQM1 will go low if the LSB of the logical address is 1.

Would you please tell me what you meant?

Best regards,
Tsutomu Furuse

Antony,

Thank you for the clarification.

Best regards,
Tsutomu Furuse