uPSD 3334 AD Conversion problem

massimo23 · ‎2004-09-17

Posted on September 17, 2004 at 14:55

lwang · ‎2011-05-17

Posted on May 17, 2011 at 12:01

In addition to programming the ACON and ADCPS registers, you need to set the bits in P1FS0 and P1FS1 that correspond to the Port1 pins you use for ADC.

The symptom you described sounds like the Port1 pins are in GPIO mode.

massimo23 · ‎2011-05-17

Posted on May 17, 2011 at 12:01

Hi forum,

One of my customer is actually using uSD3334 part for a new project in scaling applications.

The software engineer involved in it, is facing a problem with internal A/D behaviour. In particular, my customer tries to ''read'' a voltage across P1.7 pin but: at 0 V a small offset is at the pin (even decoupling AD pin from the voltage source via an operational amplifer), 0x46is the read, and then, from the voltage range from 0 to 2V the offset is about 0x64 superposed to the effective read, from 2V to 3.3V this offset reduce to 0x32 superposed to the signal.

This is fact is something like a non-linear behaviour of the AD converter.

Can you please suggest me anything that could be helpful to solve this problem?

Thanks in advance and regards.