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How to interface with a >16-bit SPI device?

TKess.1
Associate

How to interface with more than 16-bit SPI devices, like a 20-bit ADC (e.g. ADS8900B)?

All but STM32H7 have 16-bit buffers (see AN5543). Are there ways to effectively use a 'lesser' microcontroller (e.g. STM32G0 or -G4)?

3 REPLIES 3
AScha.3
Chief

on many chips SPI is 8bit only (standard), so transfer of a 24bit number is just a 3 byte spi transfer sequence.

look at ds of the adc, most use 8bit transfers.

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SSher.3
Associate III

Just use the cheapest, basically ANY STM32 with SPI. It'll do for your requirements.

20-bit ADC will send data in serial manner, 3 bytes, one byte at a time on 1-bit SPI MISO bus.​

S.Ma
Principal

If the ADC was very incompatible with MCU SPIs, they would reduce their market acceptance.

There should be something to make it easy from AD protocol design.