Analog to Digital Converter

Convert analog signal on ADC input pin to digital signal

  • Library:
  • Embedded Coder Support Package for STMicroelectronics Discovery Boards/STM32F4-Discovery

Description

Measure the voltage of an analog pin relative to the analog input reference voltage on the STM32F4-Discovery™ board. The block output emits analog voltage in varying ranges based on the conversion resolution selected for the ADC in Configuration parameters > Coder Target > ADCx.> Conversion resolution.

For example: When you select 12-bits as resolution for ADC1, the block output emits the analog voltage ranging from 0 to 4095. If the measured voltage equals the ground voltage, the block output emits 0. If the measured voltage equals the analog reference voltage, the block output emits 4095.

You can read up to 16 channels of analog signals from ADC1, ADC2, or ADC3 modules in single, continuous, scan, or discontinuous modes.

The table shows the analog pins corresponding to the channels of the ADC modules that can use these pins to measure the voltage.

For example, ADC modules 1, 2, and 3 that corresponds to channel 12 can use the PC2 pin to measure the voltage. Here, PC2 refers to pin 2 on port C.

Ports

Input

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Convert analog signal on ADC input pin to digital signal.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | Boolean | fixed point | enumerated | bus

Parameters

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The Analog to Digital Converter dialog box contains three tabs:

  • Configuration — Identify the configuration settings for the block.

  • Channel Selection — Specify the channel details for conversion.

  • Interrupts and Status flags — Set the interrupt and the flag status.

Configuration

Select an ADC module for conversion.

Select one of the following options for conversion.

  • Injected group — You can convert up to 4 analog signals. In this mode, you can ‘inject’ the ADC conversion during the conversion of regular group channels.

  • Regular group — You can convert up to 16 analog signals.

Select one of the following options for conversion.

  • Software start of conversion – Select this option to start the ADC conversion based on the software request.

  • External start of conversion – Select this option to start the ADC conversion based on the external event.

  • Trigger start of conversion after regular group (JAUTO) – Select this option to start the injected group conversion after completion of the regular group channels. This option is available only when you select Injected group in ADC conversion group.

  • Only read results — In this mode, the block output emits the analog to digital conversion result for the selected analog channel only. The block does not configure the selected ADC module.

Select the option to trigger the ADC conversion for ‘Software start of conversion’ option in ‘Block configuration’ parameter.

  • Trigger, wait and read results — Select this option to trigger ADC conversion every sample time. The block output waits until the conversion is completed and emits the results. This option is enabled when you select ‘Software start of conversion’ in ‘Block configuration’ parameter.

  • Trigger via input port — Select this option to trigger ADC conversion on input 'Trigger'. The ADC conversion is triggered when input is true. As the ADC block does not emit the conversion result, use another ADC block with 'Only read results' for ‘Block configuration’ parameter. This option helps to read the ADC conversion results in triggered or enabled subsystems.

The ADC is configured for continuous conversion mode. This option is available only when you select Regular group for ADC conversion group.

The option that you select to indicate the end of conversion after each channel conversion. This option is available only when you select Regular group for ADC conversion group.

Select the polarity of the external event based on which the ADC is triggered.

Specify how often this block reads the pin value, in seconds. Enter a value greater than zero.

Channel Selection

Select the number of channels for conversion.

Select the channel for the first conversion.

Select the channel for the second conversion. You can select an ADC channel for second conversion, if the Number of channels to be converted is more than 1.

Select the channel for the nth conversion where n = 4 for the Injected group and n = 16 for the Regular group. You can select an ADC channel for nth conversion if the Number of channels to be converted is more than 1.

Interrupts and Status flags

Select the option to emit the overrun status in the block output.

Select the option to emit the watchdog interrupt.

Select the option to emit the end of conversion interrupt.

Select the option to emit the over run status.

Select the option to emit the status about the conversion being out of the watchdog thresholds.

Select the option to emit the status about the start of conversion.

Select the option to emit the status about the end of conversion.

See Also

Introduced in R2013b