Shawon Shahryiar over at Embedded Lab has written an article discussing the basics of STM32 ADC:

The block diagram shown above might look a bit complex at first but it still worth having a look. It shows us the interfaces that are related to the ADC block and some key features. It seems that some external interrupt pins and internal timer peripherals have some kind of relation with the ADC block. Well these hardware peripherals can trigger ADC conversion. The more we go forward, the more we explore. In short I would like to point out some key features of a typical STM32 ADC:

  • 12-bit successive approximation ADC
  • Maximum ADC conversion rate is 1MHz and more than 2MHz in some STM32 families
  • A/D conversion range: 0 – 3.6V DC
  • ADC power supply operating range: 2.4V – 3.6V DC
  • ADC input range: (V_Ref- and V_Ref+ pins are available only in some devices and packages)
  • Different modes of operation available for different measurement cases
  • Dual mode conversion on devices with at least 2 ADC units. Some devices have more than 2 ADCs
  • An integrated ADC sequencer ranks channels according to order

  • Channel-by-channel sample time programmability. Having this feature is an advantage because we can set different sampling time for different channels and the ADC block need not to be stopped for making such changes
  • Several external input channels are available. 10 external channels in STM32F103C8T6
  • Two internal ADC channels available with ADC1 (aka. Master ADC). These channels are connected to an internal band gap voltage reference source and an on-chip temperature sensor
  • An Analogue Watchdog (AWD) unit can detect if an ADC channel(s) is operating within a predefined ADC count window
  • DMA-based fast data transferability
  • Several hardware interrupts are available to flag important events





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