Photon Analog pins to ARM ADCs

I know the ARM chip used in the Photon has 3 ADCs. Are they connected to specific pins or do the ADCs get allocated by the chip using some other algorithm.

I want to make sure that when I use the different Analog pins on the Photon, they are handled by the same internal ADC, how do I ensure that?

Look under here:

It tells you which are analog pins (basically A0-A7).

Looking at the data sheet:

A7 - PA0 - ADC123_IN0
A6 - PA4 - ADC12_IN4
A5 - PA7 - ADC12_IN7
A4 - PA6 - ADC12_IN6
A3 - PA5 - ADC12_IN5
A2 - PC2 - ADC123_IN12
A1 - PC3 - ADC123_IN13
A0 - PC5 - ADC12_IN15

@BDub should be able to share more from the information.

What’s the reason for wanted to use the same ADC?

Sorry I want to know that at a precise moment in time I can fire off all 3 ADCs on 3 different Analogu pins.

So from the information above it seems like some pins won’t have access to the 3rd ADC of the ARM chip. Is that correct?

I was looking for something like that, and couldn’t find it. Is it that you’re looking at? If so, how do you infer which ADC serves which pins?

If I’m interpreting what you wrote correctly, there are two ADCs: ADC12 and ADC123.

ADC12 can multiplex between A0, A3, A4, A5 & A6
ADC123 can multiplex between A1, A2 & A7

There are actually 3 ADC’s:
3 × 12-bit, 0.5 μs ADCs with up to 24 channels and up to 6 MSPS in triple interleaved mode

And if a pin is labeled as ADC123_IN12, that means it can be accessed as channel 12 on ADC 1, 2, or 3.

Checkout the datasheet: STM32F205xx (STM32F205RGY6) and reference manual RM0033 :wink:

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Have a look here (MODULE worksheet)

Or you look at the STM32F2xx datasheet and match up the GPIO pins

But doesn’t this still mean that if I wanted to sample using all 3 ADCs at exactly the same time then I am restricted to which pins I can use because most inputs cannot use ADC3 except A1,2,7?