I have the new XBee S2C RP-SMA and I’m wanting to accurately and remotely read the ambient temperature so I’ve connected up an MCP9700A Linear Active Thermistor to the XBee S2C ADC port.
I needed to calibrate the system and create a formula to translate the XBee S2C A0 ADC Reading in mV to a Temperature DegC. I found that when the A0 ADC input is connected to 0V GND the ADC reading which should be 0mV 0x00 was varying between 0x10 and 0x15. This translates to 0.5 Deg C which I was not expecting.
D0 = 2 Set D0 port to ADC
D1 = 2 Set D1 port to ADC
RP = 0 Disable all Pull-up resistors
IR = EA60 Sample every 60 Seconds
Connect: GND=0V, VSS = 3.3V, VRef = VCC 3.3V, D0 to GND 0V, D1 to the output of the MCP9700A.
Am I doing something wrong or is there a problem with the XBee S2C ADC?
I’m using the latest version of XCTU v6.2 on a Windows 7 (64bit) Workstation and the XBee S2C XB24CZ7SIT-004 is loaded with the latest Firmware Version 4059.