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I'm a novice to PCB design and circuit design. For an university project, I need to design a PCB which samples 16 different signals at a rate of 800Hz per signal (ie need total sample rate 16x800=12800 Hz) and also has BLE capabilities.

I was planning on using the ESP32-S3 microcontroller for that since it has BLE, 2 (12bit)ADCs with 10 channels each so it seemed perfect. And according to the ESP32-S3 datasheet, it can sample at 100 kHz so even more perfect.

But while reading sections 39.3.2 and 39.3.3 of the following datasheet I saw that there are two different types of controllers for the ADCs :

  • a digital controller for ADC1 with all the features I need (namely multi-channel scanning at defined interval) but which can only control the first ADC
  • Real Time Clock Controllers available for ADC1 and ADC2, which don't have these nice features (can only do single channel conversion, somehow can be configured by the ULP coprocessor whatever that means ?). ChatGPT tells me that having to issue a single channel conversion command separately for each channel at several thousand Herz could introduce a lot of latency and not work, but I don't trust ChatGPT for technical advice.

So I now have three choices :

  1. Use Digital Controller on ADC1 to monitor 10 channels (straightforward ?) and RTC controller on ADC2 to monitor 6 channels (maybe challenging ?) but I need to synchronize the two controllers which run on two different clocks, the real time and the main clock (possibly hard ?)

  2. Use RTC controllers on ADC1 and ADC2 to monitor 8 channels each (maybe challenging), but at least I don't need to synchronize anything.

  3. Simply buy external ADCs that have the desired specs and not bother with the integrated ADCs. Pros : I was told dedicated component ADCs are more precise than integrated ones and will need less code to clean/make usable the digitized signal. Cons : one more component to deal with on my PCB, I was trying to keep it simple since it's my first time.

I need advice to understand if options 1 and 2 are even feasible (before I invest way too much time in them), and how much complexity option 3 adds.

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  • \$\begingroup\$ Can you briefly explain the salient differences between this post and your earlier one: electronics.stackexchange.com/questions/740200/… \$\endgroup\$ Commented Mar 4 at 21:19
  • \$\begingroup\$ @Andyaka Indeed this post is just a more specific question trying to solve the same problem. The salient difference being that I have a specific MCU in mind with specific characteristics and I need help understanding if my problem can be solved by this MCU. I also need help with the technical implications of using an RTC controller, and overall expert advice on whether the different solutions I have in mind are even feasible or if my novice dreams will come crashing down after having invested way too much time in a solution doomed to fail. \$\endgroup\$ Commented Mar 4 at 21:38
  • \$\begingroup\$ You need to differentiate or this post may get closed as a repeat of the previous. \$\endgroup\$ Commented Mar 4 at 21:42
  • \$\begingroup\$ @Andyaka Even though the intro paragraph is very similar, I think the questions are quite different. Here I am asking about the specific technical capabilities of a specific MCU, and general design advice, while in the other one I was asking (other) general design advice. \$\endgroup\$ Commented Mar 4 at 21:47
  • \$\begingroup\$ Do not ask chatgpt or any other chatbot for advice on using electronic components. It will not give you correct or even necessarily relevant answers. \$\endgroup\$ Commented Mar 5 at 16:33

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