This tutorial demonstrates how to continously measure 6 analog inputs with an STM32F103 MPU with ADC1 and ADC2 in dual regular simultaneous mode, using DMA and Oversamling. I am using the STM HAL Hardware Abstraction Layer functions, CubeIDE as Development Environment and the integrated hardware configuration tool (CubeMX). and a 100 kOhm Potentiometer (variable resistor) Hardware Requirements: in this tutorial I am using a “Bluepill” prototyping board, with an STM32F103C8T6 MPU, along with the following hardware: The Tx Complete Interrupt is used here only to toggle the LED of the Bluepill.Ī tutorial how to use ADC1 and ADC2 of an STM32F103C8 MPU in ADC dual regular simultaneous mode, to measure 6 analog input channels with DMA, „double buffer technique“ and Oversampling. We have to check, if a buffer rollover occurred during the transmission and have to take that into account. With the information of the last known buffer position and the current buffer position we can calculate the length of the received data. This information needs to be consistent over the whole runtime of the program, so you have to store it “in a safe place” 😉 – don’t lose it … The start position of the new incoming data stream is the last end position, which can be calculated from querying the DMA “CNDTR” register (which tells us, how many bytes are left until the buffer is full / rolls over) and subtracting that value from the (known) buffer size. The incoming data is checked when the idle interrupt occurs.

If it rolls over two or more times, we can assume, that some data have been overwritten and the transmission is corrupted.

A Buffer may only roll over once before an Idle Interrupt occurs for a valid transmission. We use this interrupt to count the „Buffer rollovers“. To demonstrate this, the Rx buffer size was intentionally made very low (16 bytes) for this example. The Rx Complete Interrupt always occurs, when the Rx Buffer rolls over. There are 3 interrupts: the Rx Complete Interrupt (created by DMA), the Tx Complete Interrupt (also created by DMA) and the „Idle Line“ Interrupt, coded manually in the stm32f1xx_it.c.

Stm32 blue pill schematic clock