ADC12 differential pair & single ended mixed

[matthiasuhlmann]

Hi all,

I set up ADC12 to measure:

- ANA0 & ANA1 as differential pair

- ANA3 as single ended

- ANB0 & ANB1 as differential pair

- ANB3 as single ended

- ANB4 as single ended

i use A & B channel in triggered parallel mode and run them independent.

Problem:

sample ANB3 & ANB4 deliver complete wrong result:

=> if ADC voltage increase, ADC result decrease

Is it possible that there is a Problem on ADC12?

[xiangjun_rong]

Hi,

 have you set the SIMULT in ADCx_CTRL2 register?

BR

XiangJun Rong

[matthiasuhlmann]

Hi Xiang.Jun Rong,

No we do parallel scans independently.

BR

Matthias

Matthias Uhlmann

Engineer Software Design

Bel Power Solutions & Protection

O +41 44 944 8103

E matthias.uhlmann@psbel.com<mailto:matthias.uhlmann@psbel.com>

Ackerstrasse 56, 8610 Uster, Switzerland

belpowersolutions.com<http://belpowersolutions.com/>

[xiangjun_rong]

Hi,

Pls set the SIMULT bit and have a try. from my experience, there is incorrect sample if you clear SIMULT bit.

BR

Xiangjun Rong

[matthiasuhlmann]

But is it no problem if we need to trigger both ADC channels (A & B) independent? It is really important that first sample of both channels are placed accurate based on its sample trigger.

BR

Matthias Uhlmann

Engineer Software Design

Bel Power Solutions & Protection

O +41 44 944 8103

E matthias.uhlmann@psbel.com<mailto:matthias.uhlmann@psbel.com>

Ackerstrasse 56, 8610 Uster, Switzerland

belpowersolutions.com<http://belpowersolutions.com/>

[xiangjun_rong]

 Hi,

I suggest you set the SIMULT bit and have a try. From my experience, there is incorrect sample if you clear SIMULT bit sometimes.

BR

Xiangjun Rong

[matthiasuhlmann]

Hi Xiangjun Rong,

if SIMULT bit is set, differential samlaple is ok, but this will not work for our Need!

 We Need to trigger bot ADC Chanels Independent and Chanel B EOC Interrupt will execut Regulation Loop.

It is critical that sample is taken at a defined time to get needed result!

Is there no way to use differential samples if we Need tu run Chanel A & B independently?

Is this a bug within the ADC Modul? Why is there no errata for this behavior?

BR

Matthias

[xiangjun_rong]

Hi, Matthias,

From my experience, if you use different trigger to trigger ADCA and ADCB independently, there is abnormal sample result for only ADCB module  randomly, but the phenomenon is not documented in errata.

Hope it can help you.

BR

Xiangjun Rong