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Independent modes

2

Independent modes

The STM32F30x ADC is a 12-bit ADC successive approximation analog-to-digital converter.

This ADC has up to 19 multiplexed channels, allowing measurement of up to 16 external

sources and up to 3 internal sources. The various channels can be converted in single,

multichannel, continuous or discontinuous mode. The result of conversion is stored in a left-

or right-aligned 16-bit data register.

2.1

Regular conversion

Regular conversion can be performed for single-ended or differential inputs, in single or

continuous mode, for single channel or multichannel with programmable sampling time for

each channel.

The following sections present typical configuration procedures for each feature or mode.

2.1.1

Single or multi-channel configuration

In independent mode, the ADC channels can be used in a single or multi-channel manner.

With the ADC sequencer, you can configure any sequence of up to 16 channels

successively, with different sampling times and in different orders.

Regular channels and their order in the conversion sequence must be selected in the

ADC_SQRx registers. The total number of conversions in the regular group must be written

in the L[3:0] bits in the ADC_SQR1 register.

2.1.2

Single or continuous conversion mode

In single conversion mode, the ADC performs all channel conversions once. You can start

this mode with the CONT bit at 0 either by setting the ADSTART bit in the ADC_CR register

(for a regular channel), or through an external hardware trigger event.

In continuous conversion mode, when a software or hardware regular trigger event occurs,

the ADC performs all the regular conversions of the channels once, and then automatically

re-starts and continuously converts each conversion in the sequence. You can start this

mode with the CONT bit at 1 either through an external trigger, or by setting the ADSTART

bit in the ADC_CR register.