SPI data problem

ybenharim10 · ‎2009-09-10

Posted on September 10, 2009 at 12:03

SPI data problem

ybenharim10 · ‎2011-05-17

Posted on May 17, 2011 at 13:23

When I send data from the SPI port, the data is sometimes received ok and sometimes shifted by 1 bit left.

The received data is read by a loopback SPI port or Beagle PC analyzer.

For example: when I send 0x50,0x51,0x52,0x53

I receive something like: 0x50,0xA2,0xA4,0xA6

So it seems that 1 bit is missing.

Any ideas where the missing bit went?

ybenharim10 · ‎2011-05-17

Posted on May 17, 2011 at 13:23

The SPI port that sends the data is configured as ''master''.

jpeacock2 · ‎2011-05-17

Posted on May 17, 2011 at 13:23

Are you sure your receiver is triggering on the right clock edge? SPI can be set up to receive data on rising or falling edge. And does your receiver match clock idle (normally hi, or normally low)? Do you run the signal through any buffers or inverters?

Jack Peacock