ADC Fast and Slow Channels

eg7963 · ‎2016-04-06

Posted on April 06, 2016 at 11:17

Hi there,

Im working with the STM32F334C8xx Microcontroller , which has 2 ADC with up to 15 channels on each.

The datasheet states that for a given channel, there are up to 5 so named ''fast channels'' and 10 ''slow channels''. The main difference is in the minimal sampling time that is slightly longer in ''slow'' channels as it is in ''fast channels'', probably linked to input impedance and capacitive load on the channel.

The fact is that the datasheet is quite unclear on which channel is a ''fast channel and which one is a slow one. I would guess that this is PIN linked but i found no detail on that subject neither in datasheets, user manual or application notes.

Is anywho aware of which channels operates in fast mode and which one operates in slow mode?

Thanks

Eric

#stm32-adc-fast-channel""

Tesla DeLorean · ‎2016-04-06

Posted on April 06, 2016 at 15:20

The Reference Manual?

/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Attachments/65020/f334_adc_fast_slow.jpg

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f334_adc_fast_slow.jpg : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I1Dn&d=%2Fa%2F0X0000000blr%2FYOdDLEIt03b4.P9b2b_2bEpbhsStBcGhLWgs0E7DgHY&asPdf=false

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eg7963 · ‎2016-04-07

Posted on April 07, 2016 at 12:38

Ok

Thx for pointing that out for me ... Seems its the only page where that appears in the whole 1117 pages of the manual.

Amel NASRI · ‎2016-04-07

Posted on April 07, 2016 at 16:09

Hi go.eric,

In all STM32F3 products, (ADCx_IN1..5) are fast channels, however the others are slow.

You find this information in the reference manual as well:

There are up to 18 multiplexed channels per ADC:

â€¢ 5 fast analog inputs coming from GPIO pads (ADC_IN1..5)

â€¢ Up to 10 slow analog inputs coming from GPIO pads (ADC_IN6..15). Depending on the products, not all of them are available on GPIO pads.

Following this discussion, a request is made internally in order to add a note in the datasheet precising the FAST ADC channels in the pinout table.

-Mayla-

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