STM32 tutorial triple ADC interleaved sampling

ps： This article is based on stm32F407ZGT6 Single chip microcomputer

        stm32F4 The maximum sampling rate of single channel acquisition of single chip microcomputer is 2.4M, Therefore, it is sometimes difficult to meet higher frequency sampling , So consult the chip manual , Find out stm32F4 Support multiple ADC collection , Use the conversion time of each channel , Dislocation sampling , So as to improve the sampling rate , Turn the sampling rate to 2.4*3=7.2M.  （ I started learning last year ADC When studying , be based on cube and HAL Triple of Library ADC There are few cross sampling references , I also studied for a period of time , Write this blog, hoping to help more people .）

The schematic diagram is as follows ：

The following is an illustration of the official example ,

In this example, the system clock is 144MHz, APB2 = 72MHz and ADC clock = APB2 /2. 
Since ADCCLK= 36MHz and Conversion rate = 5 cycles 
==> Conversion Time = 36M/5cyc = 7.2Msps

This is triggered by software ADC Continuously sampled , I tried , It is feasible. . The few references on the Internet are also under the continuous conversion mode mentioned above .

But I am used to using timer to trigger sampling , Because the sampling rate is continuously adjustable , More flexible than continuous conversion .

So I started trying to trigger triple timer ADC！

The configuration is as follows ： open TIM8, Hang on APB2 On , by 144M

How much is the clock frequency configured ？

Open the chip manual ：

  Thus we can see that The trigger source only needs to trigger ADC1 ADC2 and 3 The acquisition is automatically started after the inherent time of the triple mode set by the chip

so ADC1 Just configure 2.4M  144M/60=2.4M

 ADC How to configure ？

Look at the chip manual ！

 

 DMA mode2  ！

ADC1 The configuration is as follows ：

（ Choose the channel 12 Because it is pure Less interference ）

Remember to open it. DMA !

Configuration is similar to single channel ADC＋ Timer triggered ！

ADC2/3 ditto I won't repeat it here ！

complete ！

The generated code ！

 

How to write in the code ？

Open the chip manual again ！！

So that's it ！ I feel like I can ！

Turn on ADC123 and TIM8:( Pay attention to triple ADC In alternate mode ,ADC1 There is an inherent opening function )

 

  compile ！ burn ！

Tested last year , The epidemic situation will not be tested at home QAQ

Last year, the signal generator was used to give 100khz Sine wave signal , A cycle was picked 72 A p.m. .

ps： According to the seniors, this way is unstable , When the workload of single chip microcomputer is large, it may appear bug.