Configuring ADC registers for conversion

AN3023

16/23

Doc ID 16113 Rev 1

Synchronization between two ADCs

This feature can be applied only if the device contains both ADC modules (ADC and ADC2).

The synchronization mechanism can only be used for single conversion and can be

triggered either by software or by hardware.

To start the synchronous conversion, the ADSE bit must be set to ‘1’ in the CR3 registers of

both ADC and ADC2.

When the ADS bit of the master ADC module is set, or another event triggers a conversion

on the master ADC module, a conversion on the slave module (ADC2) is triggered

synchronously.

Example 7

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Channels: AIN2 on ADC and AIN1 on ADC2

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Left alignment

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Starting ADC and ADC2 by software

For Example 7, the ADC registers should be configured as follows:

//ADC2 setting - SLAVE

ADC2_CSR:CH[3:0] = 0001

ADC2_CR1 ADON = 1;

//ADC setting - MASTER

ADC_CSR:CH[3:0] = 0010 AIN2 channel

ADC_CR1 ADON = 1;

ADC_CR3:ADSE = 1; //enable sync on ADC

ADC2_CR3:ADSE = 1; //enable sync on ADC2

ADC_CR3:ADS = 1; //ADS start trigger, parallel conversion is started

Note:

Before starting synchronization conversion, the two ADC modules have to be programmed

with the same clock prescaler values. It is recommended to program the prescaler register

before switching on the ADCs.