6551card and missing samples from a flash memory

[xela75]

Hello,

I'm using a 6551 HSDIO card and I have some troubles to acquire some data.

Here's the big deal : I use channels 0-7 to send commands to a flash nand memory and i also use this channels to read the datas that the memory then sends to me (it's a multiplexed bus).

I configured 2 sessions, one for generation and one for acquisition and when it is acquisition time, the generation session puts its channels 0-7 in high impedance.

Eventually, I can receive datas but I noticed that when i have some bytes which start with 0xFx that is to say 0xF5 or 0xFF for instances, this datas aren't acquired.

 I think it's not a software problem but a hardware one.

Products used :

 - NI PCI 6551

- SHC68-C68-D4 Cable (1m)

- CB - 2162 prototype board

I'm wondering if it would be a termination problem because there is no termination made on my CB - 2162 ? I'm running at 1Mhz so far and the problem is still there.

Have you got any ideas about my problem ?

Thank you in advance.

[ajangot]

Hello,

I didn't understand something. You have a nand memory but you have not connection to you board, so where is the memory? Have it he same ground?

regards,

[engwei]

How is your generation and acquisition clock. All set to "Rising edge" ? How about your start trigger, properly connected and configured ?

[xela75]

The memory is connected to the board with wires and a TSOP support.

Clock is configured to low level. The clock setting is " on board clock" for generation session and I export this clock to the acquisition session by the DDC connector.

Acquisition is triggered by a pattern match. 

[xela75 · Accepted solution]

Ok it works !

It was a termination problem as i said...My pcb needs a 10K parallel termination.

Thank you for helping me to think !