![\"\"](\"https:\/\/blog.embeddedexpert.io\/wp-content\/uploads\/2021\/07\/1200px-ADC_Symbol.svg_-1-1024x323.png\")
<\/figure><\/div>\n\n\n\nIn the previous guide (here<\/a>), we took a look how to configure the ADC to use DMA with multiple channel. In this guide, we shall use timer to trigger the ADC each 2 second and display the result on serial terminal.<\/p>\n\n\n\n <\/p>\n\n\n\n In this guide, we shall cover the following:<\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n The ADC configuration is similar to the ADC in DMA. However, the Continuous mode shall be disabled. Hence, the configuration is similar to the previous guide as following:<\/p>\n\n\n\n Note that the continuous mode is disable since the timer shall trigger the ADC conversion not the internal clock of the ADC.<\/p>\n\n\n\n For timer trigger ADC, we shall set the trigger to be rising edge and the source as TIM2 TRGO:<\/p>\n\n\n\n Note: Don’t enable the ADC (ADON) yet.<\/p>\n\n\n\n <\/p>\n\n\n\n Since the timer used is Time2, we need to enable clock access to timer2 and set prescaler to 16000-1 and ARR value to 2000-1. Hence those value shall give trigger each second:<\/p>\n\n\n\n Now, we shall set the Master mode selection to Update – The update event is selected as trigger output (TRGO):<\/p>\n\n\n\n <\/p>\n\n\n\n The DMA configuration is similar to part 3 except that there will be interrupt when transfer is completed.<\/p>\n\n\n\n Finally, enable DMA stream, ADC and timer in this order:<\/p>\n\n\n\n For interrupt handler:<\/p>\n\n\n\n For main.c :<\/p>\n\n\n\n <\/p>\n\n\n\n You may the download the source code from here:<\/p>\n\n\n\n <\/p>\n\n\n\n After compiling and upload the code, open serial terminal application and set the baudrate to 115200<\/p>\n\n\n\n The values shall be update each 2 seconds<\/p>\n\n\n\n <\/p>\n\n\n\n Happy coding \ud83d\ude42 <\/p>\n","protected":false},"excerpt":{"rendered":" In the previous guide (here), we took a look how to configure the ADC to use DMA with multiple channel. In this guide, we shall use timer to trigger the ADC each 2 second and display the result on serial terminal. In this guide, we shall cover the following: ADC Configuration. Timer Configuration. DMA Configuration. […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,2,11,12],"tags":[],"class_list":["post-972","post","type-post","status-publish","format-standard","hentry","category-data-structures","category-embedded-systems","category-peripheral-drivers","category-stm32"],"_links":{"self":[{"href":"https:\/\/blog.embeddedexpert.io\/index.php?rest_route=\/wp\/v2\/posts\/972"}],"collection":[{"href":"https:\/\/blog.embeddedexpert.io\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.embeddedexpert.io\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.embeddedexpert.io\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.embeddedexpert.io\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=972"}],"version-history":[{"count":1,"href":"https:\/\/blog.embeddedexpert.io\/index.php?rest_route=\/wp\/v2\/posts\/972\/revisions"}],"predecessor-version":[{"id":977,"href":"https:\/\/blog.embeddedexpert.io\/index.php?rest_route=\/wp\/v2\/posts\/972\/revisions\/977"}],"wp:attachment":[{"href":"https:\/\/blog.embeddedexpert.io\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=972"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.embeddedexpert.io\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=972"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.embeddedexpert.io\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=972"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}1. ADC configuration:<\/h2>\n\n\n\n
\t\/*Enable clock access to GPIOA and GPIOC*\/\n\tRCC->AHB1ENR|=RCC_AHB1ENR_GPIOAEN|RCC_AHB1ENR_GPIOCEN;\n\t\/*Configure the pins in ADC mode*\/\n\tGPIOA->MODER|=GPIO_MODER_MODER3;\n\tGPIOC->MODER|=GPIO_MODER_MODER0;\n\n\t\/*Enable clock access to ADC1*\/\n\tRCC->APB2ENR|=RCC_APB2ENR_ADC1EN;\n\t\/*Enable scan mode*\/\n\tADC1->CR1|=ADC_CR1_SCAN;\n\t\/*Enable continuous\/ DMA and DDS*\/\n\tADC1->CR2|=ADC_CR2_DDS|ADC_CR2_DMA;\n\t\/*Set length to 2 channels*\/\n\tADC1->SQR1|=(1<<20);\n\t\/*Set ch3 first first and ch10 second in the conversion sequence*\/\n\tADC1->SQR3|=(3<<0)|(10<<5);<\/pre><\/div>\n\n\n\n
![\"\"](\"https:\/\/blog.embeddedexpert.io\/wp-content\/uploads\/2022\/05\/Screen-Shot-2022-05-28-at-5.43.15-PM-1024x330.png\")
<\/figure>\n\n\n\n\/*Select TIMER2_CH2 as trigger source*\/\n\tADC1->CR2\t\t\t|=ADC_CR2_EXTEN_0;\n\tADC1->CR2\t\t\t|=ADC_CR2_EXTSEL_3|ADC_CR2_EXTSEL_1|ADC_CR2_EXTSEL_0;<\/pre><\/div>\n\n\n\n
2. Timer Configuration:<\/h2>\n\n\n\n
\t\/*Configure the timer*\/\n\tRCC->APB1ENR\t\t|=RCC_APB1ENR_TIM2EN;\n\tTIM2->PSC\t\t\t =16000-1;\n\tTIM2->ARR\t\t\t =2000-1;<\/pre><\/div>\n\n\n\n
![\"\"](\"https:\/\/blog.embeddedexpert.io\/wp-content\/uploads\/2022\/05\/Screen-Shot-2022-05-28-at-5.50.31-PM-1024x316.png\")
<\/figure>\n\n\n\n\tTIM2->CR2\t\t\t|=TIM_CR2_MMS_1;<\/pre><\/div>\n\n\n\n
3. DMA configuration:<\/h2>\n\n\n\n
\/*Enable clock access to DMA2*\/\n\tRCC->AHB1ENR|=RCC_AHB1ENR_DMA2EN;\n\t\/*Disable the strsam*\/\n\tDMA2_Stream0->CR&=~DMA_SxCR_EN;\n\t\/*Wait until the stream is disabled *\/\n\twhile(DMA_SxCR_EN==(DMA2_Stream0->CR&DMA_SxCR_EN));\n\t\/*Set memory size to half-word*\/\n\tDMA2_Stream0->CR|=DMA_SxCR_MSIZE_0;\n\t\/*Set peripheral size to half word*\/\n\tDMA2_Stream0->CR|=DMA_SxCR_PSIZE_0;\n\t\/*Enable memory increment*\/\n\tDMA2_Stream0->CR|=DMA_SxCR_MINC;\n\t\/*Enable circular mode*\/\n\tDMA2_Stream0->CR|=DMA_SxCR_CIRC;\n\t\/*Enable Transfer complete interrupt*\/\n\tDMA2_Stream0->CR|=DMA_SxCR_TCIE;\n\tNVIC_EnableIRQ(DMA2_Stream0_IRQn);\n\t\/*Set number of transfer to 2*\/\n\tDMA2_Stream0->NDTR=2;\n\t\/*Set peripheral address to ADC1->DR*\/\n\tDMA2_Stream0->PAR=(uint32_t)&(ADC1->DR);\n\t\/*Set memory address to adc_data*\/\n\tDMA2_Stream0->M0AR=(uint32_t)&(adc_data);<\/pre><\/div>\n\n\n\n
\/*Enable the DMA stream*\/\n\tDMA2_Stream0->CR|=DMA_SxCR_EN;\n\t\/*Enable the ADC*\/\n\tADC1->CR2|=ADC_CR2_ADON;\n\t\/*Start the timer *\/\n\tTIM2->CR1\t\t\t|=TIM_CR1_CEN;<\/pre><\/div>\n\n\n\n
\nvoid DMA2_Stream0_IRQHandler(void)\n\t\t{\n\n\t\tif(((DMA2->LISR)&DMA_LISR_TCIF0))\n\t\t\t\t{\n\t\t\t\tfinished=1;\n\t\t\t\tGPIOB->ODR^=GPIO_ODR_OD7;\n\t\t\t\tDMA2->LIFCR=DMA_LIFCR_CTCIF0;\n\t\t\t\t}\n\t\tNVIC_ClearPendingIRQ(DMA2_Stream0_IRQn);\n\t\t}\n<\/pre><\/div>\n\n\n\n#include "stm32f7xx.h"\n#include "uart.h"\n#include "stdlib.h"\n#include "adc_dma.h"\nuint16_t data[2];\n\nvolatile int finished;\nint main()\n\t{\n\t SCB->CPACR |= ((3UL << 10*2)|(3UL << 11*2));\n\t RCC->AHB1ENR|=RCC_AHB1ENR_GPIOBEN;\n\tGPIOB->MODER|=GPIO_MODER_MODER7_0;\n\tGPIOB->MODER&=~GPIO_MODER_MODER7_1;\n\tSCB_EnableDCache();\n\tSCB_EnableICache();\n\tuart3_tx_init();\n\tprintf("uart is ready\\r\\n");\n\tadc_dma_2ch_timer_init();\n\twhile(1)\n\t\t{\n\t\t\tif(finished==1)\n\t\t\t\t{\n\t\t\t\t\tfinished=0;\n\t\t\t\t\tdata[0]=ReadChannel(A0);\n\t\t\t\t\tdata[1]=ReadChannel(A1);\n\t\t\t\t\tprintf("ADC values A0=%d, A1=%d\\r\\n",data[0],data[1]);\n\n\t\t\t\t}\n\t\t}\n\n\t}\n\nvoid DMA2_Stream0_IRQHandler(void)\n\t\t{\n\n\t\tif(((DMA2->LISR)&DMA_LISR_TCIF0))\n\t\t\t\t{\n\t\t\t\tfinished=1;\n\t\t\t\tGPIOB->ODR^=GPIO_ODR_OD7;\n\t\t\t\tDMA2->LIFCR=DMA_LIFCR_CTCIF0;\n\t\t\t\t}\n\t\tNVIC_ClearPendingIRQ(DMA2_Stream0_IRQn);\n\t\t}\n<\/pre><\/div>\n\n\n\n4. Code:<\/h2>\n\n\n\n
5. Results:<\/h2>\n\n\n\n
![\"\"](\"https:\/\/blog.embeddedexpert.io\/wp-content\/uploads\/2022\/05\/Screen-Shot-2022-05-28-at-5.54.52-PM-1024x515.png\")
<\/figure>\n\n\n\n