s_cihan_tek
Full Member level 2
Hi all,
I'm trying to use the ADC on the ezDSP F2812 development board.
I made a simple voltage divider in a breadboard using resistors and
then buffered it with a voltage follower before sending it to the
ADC pin for experimenting with the ADC. The breadboard is powered by
a 3V3 voltage regulator. (It doesn't take it power from the board)
When i looked at the output values of the ADC while debugging in CCS,
i saw that the output values of the ADC aren't 1101 and fluctuate btw
1000-1300 for an input voltage of 812mV. What could be the reason of this?
Another weird thing is, when i measured the voltage between the pins
ADCINA0(P9-PIN2) and GND(P9-PIN1) after the circuit on the breadboard is powered off, i saw 0.450V. Similarly, there were 0.730V btw
these pins when i left them floating. I don't know if this is a problem.
I'm using the internal voltage reference and a slow ADC clock
(2.5Mhz). I also made all ADC connections as in the example thermoelectric cooler design in TI appnote SPRA873 and ADC ref. guide. (AGND and VREFLO are connected etc.).
Thanks in advance
I'm trying to use the ADC on the ezDSP F2812 development board.
I made a simple voltage divider in a breadboard using resistors and
then buffered it with a voltage follower before sending it to the
ADC pin for experimenting with the ADC. The breadboard is powered by
a 3V3 voltage regulator. (It doesn't take it power from the board)
When i looked at the output values of the ADC while debugging in CCS,
i saw that the output values of the ADC aren't 1101 and fluctuate btw
1000-1300 for an input voltage of 812mV. What could be the reason of this?
Another weird thing is, when i measured the voltage between the pins
ADCINA0(P9-PIN2) and GND(P9-PIN1) after the circuit on the breadboard is powered off, i saw 0.450V. Similarly, there were 0.730V btw
these pins when i left them floating. I don't know if this is a problem.
I'm using the internal voltage reference and a slow ADC clock
(2.5Mhz). I also made all ADC connections as in the example thermoelectric cooler design in TI appnote SPRA873 and ADC ref. guide. (AGND and VREFLO are connected etc.).
Thanks in advance