Swapping in DDRAM3
Khai , 07-05-2016, 09:49 PM
Hi Robert Feranec,
Can you make a video about swapping in DDRAM? I don't understood more about swapping, can you help me?
Can you make a video about swapping in DDRAM? I don't understood more about swapping, can you help me?
robertferanec , 07-06-2016, 06:15 PM
Hi @Khai, I put it on my todo list
Don't forget. It is very important that you use the correct DQS and DQM signals for the specific data byte. That is especially important when you decide to swap the whole bytes - together with the DATA byte, you have to move also DQS and DQM signals.
For example:
- Let's say, you have data group with signals DQ0-DQ7,DQS0, DQM0. For bit swapping, based on the note above you can not move DQ0, DQS, DQM, but you can swap signals DQ1-DQ7 between them
- If you have groups DQ0-DQ7,DQS0, DQM0 and DQ8-DQ15,DQS1, DQM1, you can swap them, but you have to swap the groups completely (all the signals)
For swapping, there is a build in feature in Altium, but normally I just simply move the nets in schematic and re-synchronize the PCB.
Don't forget. It is very important that you use the correct DQS and DQM signals for the specific data byte. That is especially important when you decide to swap the whole bytes - together with the DATA byte, you have to move also DQS and DQM signals.
For example:
- Let's say, you have data group with signals DQ0-DQ7,DQS0, DQM0. For bit swapping, based on the note above you can not move DQ0, DQS, DQM, but you can swap signals DQ1-DQ7 between them
- If you have groups DQ0-DQ7,DQS0, DQM0 and DQ8-DQ15,DQS1, DQM1, you can swap them, but you have to swap the groups completely (all the signals)
For swapping, there is a build in feature in Altium, but normally I just simply move the nets in schematic and re-synchronize the PCB.
Khai , 07-08-2016, 02:50 AM
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