Made some fixes concerning the communication with the ADS1248 chip.
- Fixed SPI send function that was causing an infinite loop
- Initializing the chip select (CS) pins to be high at the beginning
- Stopped using the pin assigned to the start conversion output for the ADS1248 as a PWM output
- Fixed the SPI commands (register addresses) to the ADS1248 chip
- Fixed the data ready signal polarity from the ADS1248 chip in the interrupt handler
- Fixed the initial choice of ADC inputs for the ADS1248
- Turned on the internal voltage reference in the ADS1248 which is necessary for the Pt1000 excitation currents
- Set the ADS1248 PGA gain back to 16x
Reassigned the debug output signal to from PD6 to PA7 because PD6 is used as SPI chip select for the second ADS1248 chip.
Removed code for measurements of Pt1000 sensors using the internal ADC.
Fixed the port number for the debug signal output.
Fixed two omissions when the Pt1000 measurements with the on-chip ADC were removed.