voltage changing using ADC in MSP430
July 22, 2011
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This thing happened quite a long time a go, but I think I just want to write it anyway.
I was trying to use two ADC10 inputs in MSP430G2231 in order to produce a controllable PWM. This is the schematic for ADC inputs that I used (using simple voltage divider) :
And it’s working. I mean, it can produced PWM. Then, I decided to check the voltage in ADC inputs. First, I check each voltage in voltage divider output (ADC1 and ADC2). After that, I connect the voltage divider to the ADC input port in MSP430G2231 (P1.0 and P1.1) and check the voltage back.
Here was the result that I got:
Then, I tried to improvise by turn off the power source (both MSP and Voltage divider) for a short time and turn it on again, then measure it back. This was the result that I got:
But, if I turn of the power source (both MSP and Voltage divider) for quite a long time and turn it on again , the result was like the first measurement (before I turn it off).
Okay, this was not what I expected… Still got no clue, I decided to ask about it in a forum. Luckily, I got a quick response and it turn out that the solution was really simple.
Here’s what he wrote:
“Are the Rx, Tx, and LED0 jumpers in place? Remove them and test again.”
Following his suggestion, now my problem has been solved. Looks like even the tiniest thing sometimes can cause big problem.. 🙂