OK.
I've got a PIC18F26K22 connected to a MAX31855 thermocouple IC. The PIC is set to master SPI mode. To read the temperature and status etc. from the IC, you simply read 4 bytes.
If I scope the output of the serial data out of the chip with the wire disconnected from my PIC, the trace looks good, and the various bits appear correct (eg. If I short the thermocouple to ground or open circuit the thermocouple, bits 0 and 1 change from a 0 to a 1).
If I connect this wire to my PIC's serial data in line, the trace is erratic on the serial data line, and if I short or open the thermocouple, the bits that changed before do not change.
I'm sure the PIC is set up correctly as I have an LCD connected to the clock pin and the serial data out pin. What can be causing this problem I have.
I've got a PIC18F26K22 connected to a MAX31855 thermocouple IC. The PIC is set to master SPI mode. To read the temperature and status etc. from the IC, you simply read 4 bytes.
If I scope the output of the serial data out of the chip with the wire disconnected from my PIC, the trace looks good, and the various bits appear correct (eg. If I short the thermocouple to ground or open circuit the thermocouple, bits 0 and 1 change from a 0 to a 1).
If I connect this wire to my PIC's serial data in line, the trace is erratic on the serial data line, and if I short or open the thermocouple, the bits that changed before do not change.
I'm sure the PIC is set up correctly as I have an LCD connected to the clock pin and the serial data out pin. What can be causing this problem I have.