Which ARM has the most (muxable) ADC inputs? - Page 1
Forum section: electronics / general

author: dav888
author_rank: Regular Contributor
timestamp: December 17, 2020, 07:01:58 pm
content: As most part-selectors just allow you to select type of ADC and bits, finding out info about how many pins that can be muxed into the ADC is time consuming (reading through datasheets)......so!anyone with some hot tips on M0's M4's M33's etc that has a vast amount of analog muxes built-in? i.e. more than 16

author: dav888
author_rank: Regular Contributor
timestamp: December 17, 2020, 07:06:35 pm
content: The PSoC "Analog co-processor" CY8C4A45LQI-483 is quite impressivecan do 38ch muxable to either a 12-bit SAR ADC or a 10-bit single-slope ADCdrawback, quite rare, cost just above $3, so way above the average M0's

author: Selectech
author_rank: Regular Contributor
timestamp: December 17, 2020, 07:14:32 pm
content: Silabs EFM32PG1 / PG12 ( M4 ) allow just about all pins on a package to be used as analog input to ADC. EFM32GG11 has a few pins that can't be analog, but most available. Definitely more that 16 in all cases. Dual 12 bit ADC ( PG12 / GG11 ) with oversampling. I use a lot of them.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 17, 2020, 07:25:26 pm
content: Easily searched on DK.https://www.digikey.com/short/z191wwI see 20 to 77, even a few over 100 inputs if you don't mind they're not ARM I think.Not sure how easy they are to use. The top results look ordinary. The big ones, might be they're just crossbarring the entire chip, and iterating through them is a PITA because of myriad alternate configurations everywhere, or something. Well, just write a few functions for that, right. Might not be very noise-immune: there's reason why this isn't usually done.Or just toss in a wad of 74HC4051s: cheaper, no noise, infinitely scalable. Until you run out of bandwidth, of course, but I'm guessing that's pretty low since muxing is acceptable in the first place.Tim

author: dmendesf
author_rank: Frequent Contributor
timestamp: December 17, 2020, 09:29:17 pm
content: Stm32f303 has 32 or more inputs muxable in 4 ADCs, stm32g4 has about 36 into 5 ADCs.

author: brucehoult
author_rank: Super Contributor
timestamp: December 17, 2020, 09:51:36 pm
content: Quote from: dav888 on December 17, 2020, 07:01:58 pmYou'd think it would be pretty hard to mux a lot of ADCs while retaining accuracy. Much harder (and therefore more expensive) than muxing digital pins -- and harder than muxing the *outputs* of the ADCs.

author: JXL
author_rank: Regular Contributor
timestamp: December 18, 2020, 06:49:19 am
content: TI MSP432P401R has 24 input MUX

author: aheid
author_rank: Regular Contributor
timestamp: December 21, 2020, 07:39:00 am
content: Quote from: dav888 on December 17, 2020, 07:01:58 pmBut a few do allow you to select number of channels... for example DigiKey and ST.On DigiKey the (low-volume) cheapest ARM core with the most channels seems to be the STM32G473VBT6, with its 42 ADC channels (5 ADCs) in a LQFP-100 package.For STM32 parts I like to use the STM32CubeIDE parts selector directly, as is quicker than the web selector and it has bulk prices as well which usually correlates well with DigiKey.:https://www.digikey.com/short/z12zd2:ST product selector:https://www.digikey.com/en/products/detail/stmicroelectronics/STM32G473VBT6/10326722

author: dav888
author_rank: Regular Contributor
timestamp: December 31, 2020, 01:21:02 am
content: thanks for all the tips!!(I somehow don't get notified on replies unless I remember to click it right after posting)the efm32's are nice and cheap. good catch with their analog muxing capabilities.but like tim said, as long as you have one or a few inputs on your ARM, adding 74HC4051s will do the job!...but, one 74HC4051 is $0.3-0.4 per added 8channels, so it quickly adds up if you need say more than 32 inputs, price is almost 1:1 getting another low-cost ARM