ADC MSP430F5438

You will really need to provide more information before anyone can help you. What is your input voltage range? Reference? Clock Source? Sampling Time? etc etc etc.

The maximum input voltage is 3.3, the reference is 2.5, the clock is also 32K and 32K sampling

Hi,

in errata sheet for 54xxA there is a description ADC27. Although the clock is only 32K, it could help to set the and ADC12REFOUT resp. to set REFON and REFOUT bits in REFCTL0.

Regards!

We tested in a microcontroller MSP430F5419, with the same code, and it worked. We need help to find out why it does not work in the microcontroller MSP430F5438A.

Best regards.

Fernando

Are you going to provide us with some information (like a simple test case or how you are configuring the device) or are you expecting "psychic debugging" from us?

One idea: MSP430F5438A has a REF-Modul, 5419 has none. Do you clear the REFMSTR-Bit in FEFCTL0-Register of 5438A?

If not, you have to setup the REF-Modul, see USER´s guide. If that is not the solution, some more information must be given...

Regards!

Indeed that was the problem, since the microcontroller version "A" have the REF module unlike the "not A" and you have to configure it. We did and the ADC began to function properly.

Thank you very much to all!

Best regards

ARES ARES said:

the clock is also 32K and 32K sampling

First, note that the ADC takes 13 clock cycles for conversion, no tto count the sampling time.
With 32kHz ADC clock,the sampled charge will leak away long befor ethe conversion is done. The datasheet tells a minimum ADC clock of 400kHz for reliable results. Below, (or above the smaximum of ~5MHz) the results are not mor than a rough guessing. If at all.