Differences

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--- stm32:peripherals:dma [2016/09/21 09:28] – created feur
+++ stm32:peripherals:dma [2022/12/28 07:50] (current) – ruan
@@ Line 1: / Line 1: @@
 ====== Direct Memory Access ======
+The two DMA controllers can be used to quickly transfer data between two peripherals (or memory) without any CPU interaction. \\
+Not all combinations of peripherals are possible: available [[dma_connection|DMA connections]]. \\
+\\ {{dma_complete.svg?700em}} \\ \\
+===== Features =====
+  * 8 streams for each DMA controller, up to 8 channels per stream.
+  * 4 (32 bit wide) FIFO buffers per stream.
+  * Programmable priority.
+\\
+===== Configuration Registers =====
+==== DMA_SxCR - Stream X configuration register ====
+\\ {{dma_reg_sxcr.svg}} \\ \\
+|< 100% 5em 5em 15em 5em >|
+|EN|0|Stream disabled (reset state)||
+|:::|1|Stream enabled (reset state)||
+|CHSEL|xxx|Channel nr selected (0..7)||
+|CIR|0|Circular mode disabled (reset state)||
+|:::|1|Circular mode enabled||
+|DIR|00|Direction peripheral to memory (reset state)||
+|:::|01|Direction memory to peripheral||
+|:::|10|Direction memory to memory||
+|:::|11|reserved||
+|PSIZE*|00|Peripheral size 8 bit (reset state)||
+|:::|01|Peripheral size 16 bit||
+|:::|10|Peripheral size 32 bit||
+|:::|11|reserved||
+|MSIZE*|00|Memory size 8 bit (reset state)||
+|:::|01|Memory size 16 bit||
+|:::|10|Memory  size 32 bit||
+|:::|11|reserved||
+* Only writeable if EN = '0' \\ \\
+==== DMA_SxPAR - Stream X peripheral address register ====
+\\ {{dma_reg_sxpar.svg}} \\ \\
+|< 100% 5em >|
+|NDT|xxx|Number of data items to be transfered.|
+==== DMA_SxM0AR - Stream X memory 0 address register====
+\\ {{dma_reg_sxm0ar.svg}} \\ \\
+|< 100% 5em >|
+|M0A|xxx|Base address of memory 0.|
+==== DMA_SxM1AR - Stream X memory 1 address register ====
+\\ {{dma_reg_sxm1ar.svg}} \\ \\
+|< 100% 5em >|
+|M1A|xxx|Base address of memory 1.|
+==== DMA_SxNDTR - Stream X number of data register ====
+\\ {{dma_reg_sxndtr.svg}} \\ \\
+|< 100% 5em >|
+|NDT|xxx|Number of data items to be transfered.|
+===== Programming Example =====
+The code snippet below shows how to configure and use the DMA controller.
+<code c>
+#include "reg_stm32f4xx.h"
+RCC->AHBENR[0] |= (0x1 << 22u);      /* Enable DMA2 clock */
+/* Configure DMA2 controller. */
+DMA2->STREAM[0].CR |= (2u << 25u);   /* Setup channel. */
+DMA2->STREAM[0].CR |= (0x0 << 6u);   /* Setup direction. */
+DMA2->STREAM[0].CR |= (0x1 << 8u);   /* Setup circular mode. */
+DMA2->STREAM[0].NDTR |= 1u;          /* Setup nr of transfers. */
+/* Setup source and destination. */
+DMA2->STREAM[0].PAR |= (uint32_t) &(ADC3->DR);
+DMA2->STREAM[0].M0AR |= (uint32_t) &(TIM3->CCR[0]);
+/* Setup buffer size. */
+DMA2->STREAM[0].CR |= (0x1 << 11u);  /* PSIZE */
+DMA2->STREAM[0].CR |= (0x1 << 13u);  /* MSIZE */
+/* Start DMA transfer. */
+DMA2->STREAM[0].CR |= (0x1 << 0u);
+</code>
+\\