topic To operate EQADC and SDADC with together on MPC5777C in MPC5xxx

To operate EQADC and SDADC with together on MPC5777C

berat24 — Tue, 19 Apr 2022 13:30:00 GMT

Hello everyone,

I would like to learn whether I can use SDADC and EQADC on same channel at the same time or not.

Sincerely.

Re: To operate EQADC and SDADC with together on MPC5777C

petervlna — Wed, 20 Apr 2022 07:02:48 GMT

Hello,

Hmm, I am confused a bit.

There are Two EQADC modules, each containing two internal ADCs and Four Sigma-Delta (SD) ADC modules.

Each ADC module has its own channels. So I am not sure what the question is here. You cannot measure eQADC channel with SDACD as it is its internal IP separate from SDACD.

But if you are referring to the same pin which you like to measure then only one ADC can be routed to it at the time.

I am not sure what you are trying to achieve, but redundant measurements can be done.

Best regards,

Peter

Re: To operate EQADC and SDADC with together on MPC5777C

berat24 — Wed, 20 Apr 2022 12:43:39 GMT

Hi @petervlna

First of all thank you for your response.

I would like to ask my question in a different way.

There is a photo below. ANA0_SDA0 analog channel has been dedicated for EQADC and SDADC. Can I read data from this channel with EQADC and SDADC at the same time?

I hope, I can explain my question more clearly.

Re: To operate EQADC and SDADC with together on MPC5777C

petervlna — Thu, 21 Apr 2022 11:30:51 GMT

Hello,

Yes, it is possible to read data from that channel with both ADCs but it is not recommended to do so due to sharing of charge. It just not make any sense.

If you need redundant measurement, simply connect same signal on 2 pins and use 2 ADCs. Make sure pins are not close to each other.

Best regards,

Peter

Re: To operate EQADC and SDADC with together on MPC5777C

petervlna — Thu, 21 Apr 2022 11:40:59 GMT

Hello,

Here is closer explanation.

In the chapter 3.8.1 Enhanced Queued Analog-to-Digital Converter (eQADC) below Table 17. eQADC conversion specifications (operating): “The eQADC parameters in the above table are not guarantee when SDADC will be used on the same pin.”
3.8.2 Sigma-Delta ADC (SDADC) below Table 18. SDADC electrical specifications: “The SDADC parameters in the above table are not guarantee when eQADC will be used on the same pin.”

best regards,

Peter