These thresholds are programmed in the 12 least significant bits of the ADC_HTR and ADC_LTR 16-bit registers. The AWD analog watchdog status bit is set if the analog voltage converted by the ADC is below a low threshold or above a high threshold. After the start of ADC conversion and after 14 clock cycles, the EOC flag is set and the 16-bit ADC Data register contains the result of the conversion. The ADC needs a stabilization time of t STAB before it starts converting accurately. The total number of conversions in the injected group must be written in the L bits in the ADC_JSQR register. The injected channels and their order in the conversion sequence must be selected in the ADC_JSQR register. The Injected Group is composed of up to 4 conversions. The total number of conversions in the regular group must be written in the L bits in the ADC_SQR1 register. The regular channels and their order in the conversion sequence must be selected in the ADC_SQRx registers. The Regular Group is composed of up to 16 conversions. For instance, it is possible to do the conversion in the following order: Ch3, Ch8, Ch2, Ch2, Ch0, Ch2, Ch2, Ch15. A group consists of a sequence of conversions that can be done on any channel and in any order. It is possible to organize the conversions in two groups: regular and injected. The RCC controller has a dedicated programmable Prescaler for the ADC clock, and it must not exceed 14 MHz. The ADCCLK clock provided by the Clock Controller is synchronous with the PCLK2 (APB2 clock). DMA request generation during regular channel conversion.ADC input range: V REF– ≤ V IN ≤ V REF+.ADC conversion time: 1 µs at 56 MHz (1.17 µs at 72 MHz).Dual-mode (on devices with 2 ADCs or more).External trigger option for both regular and injected conversion.Channel by channel programmable sampling time.Data alignment with in-built data coherency.Scan mode for automatic conversion of channel 0 to channel ‘n’.Interrupt generation at End of Conversion, End of Injected conversion and Analog watchdog event.The ADC input clock is generated from the PCLK2 clock divided by a Prescaler and it must not exceed 14 MHz. The analog watchdog feature allows the application to detect if the input voltage goes outside the user-defined high or low thresholds. The result of the ADC is stored in a left-aligned or right-aligned 16-bit data register. A/D conversion of the various channels can be performed in single, continuous, scan, or discontinuous mode. It has up to 18 multiplexed channels allowing it to measure signals from sixteen external and two internal sources. The STM32F103C8 (Blue Pill) & STM32F432KC have a 12-bit ADC which is a successive approximation analog-to-digital converter. The ADC Tutorial down below is a complete introductory guide for this topic and highly recommended. And the flexibility also to make a lot of decisions like sacrificing resolution in exchange for a higher resolution or having the ADC to trigger on an internal timer signal to periodically sample the analog channels, and much more as we’ll see in this tutorial.įor those who like to have a solid introduction in ADC, how it works at the low level, different types of ADCs, ADC errors, equations, and all other details. Therefore, it’s a valuable resource in microcontrollers and different manufacturers provide us (the firmware engineers) with various features so as to make the best use of it. The ADC is one of the most expensive electronic components especially when it does have a high sampling rate and high resolution. The ADC does the counter operation that of a DAC, while an ADC (A/D) converts analog voltage to digital data the DAC (D/A) converts digital numbers to the analog voltage on the output pin. And it performs a process called quantization so as to decide on the voltage level and its binary code that gets pushed in the output register. The ADC samples the analog input whenever you trigger it to start conversion. And let’s get right into it!Īnalog-To-Digital Converters (ADC) PrefaceĪn ADC (Analog-To-Digital) converter is an electronic circuit that takes in an analog voltage as input and converts it into digital data, a value that represents the voltage level in binary code. We’ll get into the functional description for the ADC in STM32 microcontrollers, how it works, and how to configure it and make the best use of it. Starting with an introduction for the ADC as a digital circuit and then shifting the attention to the STM32 ADC hardware and its features. In this tutorial, we’ll discuss the STM32 ADC (Analog-To-Digital Converter) module. Previous Tutorial Tutorial 23 Next Tutorial STM32 ADC Tutorial – Complete Guide With Examples STM32 Course Home Page □
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