Monitoring SPI data lines

Ductapemaster

Hey all, it's been a while since I've been in the forums here. I had a full time internship during the summer and I have started college at UCSB (Computer Engineering major) which has been taking up most of my time.

Nevertheless, the project gears are still turning and I am in need of a little assistance. I am trying to find a way to monitor (or tap, so to speak) an existing serial (SPI) connection. I want to be able to see the data on both the Rx and Tx lines without interfering with the communication. I'm exploring smart card protocols with some existing hardware and I don't feel like disassembling the whole thing when I can tap into the data stream (plus its a challenge).

A hardware or a software solution is fine. Anyone have any ideas?

Thanks,

Dan

Dave Paton

A couple of BS2s and a pair of SHIFTINs? It's worked for me in the past, using parts I had laying around....

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This is not a sig. This is a duck. Quack.

Velocit

As long as the SX's pins are set to input (as they should be), the introduced connections to the SPI lines should be high-impedance and not interfere with the communications. If they do, you might need some sort of a buffer circuit.

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-Paul