Configuring ADC registers for conversion

AN3023

12/23

Doc ID 16113 Rev 1

Practical use

Continuous conversion mode is useful for collecting a set of analog values from an external

analog signal (for example, to read an AC voltage waveform).

Single scan mode

Single scan mode is started by triggering a conversion while the SCAN bit is set in the

ADC_CR2 register and the CONT bit is 0 in the ADC_CR1 register. The scan is performed

from channel 0 up to the channel n programmed in bits CH[3:0] in register ADC_CSR.

Do not clear the SCAN bit while the conversion sequence is in progress. Single scan mode

can be stopped immediately by clearing the ADON bit in the ADC_CR1 register.

Example 3

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Single scan mode from AIN0 to AIN5 channel

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Right alignment

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Starting ADC by software

For Example 3, the ADC registers should be configured as follows:

ADC_CR1:SPSEL[2:0] = 010

ADC_CSR:CH[3:0] = 0101

ADC_CR1:ADON = 1

ADC_CR2:SCAN = 1

ADC_CR2:ALIGN = 1

ADC_CR1:ADON = 1

Wait (ADC_CSR:EOC = 1)

Read the result of the conversion in ADC_DBxRH and ADC_DBxRL data buffer registers,

where x = 0..5.

Practical use

Single scan mode is useful for collecting different analog values from external sensors. This

conversion mode permits a faster conversion operation than the simple single conversion

mode (which requires conversion to be performed channel per channel).

Continuous scan mode

Continuous scan mode is started by triggering a conversion while the SCAN bit is set in the

ADC_CR2 register and CONT bit is set in the ADC_CR1 register. The scan is performed

from channel 0 up to the channel n programmed in bits CH[3:0], and, when the EOC bit is

set, a new scan is started automatically. The data buffer registers must be read before the

completion of new scan sequence, otherwise the data buffers are overwritten.

Do not clear the SCAN bit while scan conversion is in progress. Continuous scan mode can

be stopped immediately by clearing the ADON bit in the ADC_CR1 register. Alternatively, if