Hello all,
I have 2 MCUs talking to each other using SPI @ 5Mhz and I get data error very often (about 50% of the time). When I connect the scope to look at the SPI Clock, the error suddenly goes away.
I found that even when I disconnect the probe from the scope and the ground clip from the board (only the tip of the probe is connected to the SPI Clock), the error can also be eliminated. I tried putting a 10pF cap from the Clock signal to ground, but the problem is still there.
There is no spikes on the SPI Clock. The probe is Tektronix P6138A and its spec can be found here
http://www.testmart.com/sp.cfm/PROBES/TEK/P6138A.html
What's my problem?
James
I have 2 MCUs talking to each other using SPI @ 5Mhz and I get data error very often (about 50% of the time). When I connect the scope to look at the SPI Clock, the error suddenly goes away.
I found that even when I disconnect the probe from the scope and the ground clip from the board (only the tip of the probe is connected to the SPI Clock), the error can also be eliminated. I tried putting a 10pF cap from the Clock signal to ground, but the problem is still there.
There is no spikes on the SPI Clock. The probe is Tektronix P6138A and its spec can be found here
http://www.testmart.com/sp.cfm/PROBES/TEK/P6138A.html
What's my problem?
James