From 811f565322517a8c92cd92bb2c39d6a5efd8fa6d Mon Sep 17 00:00:00 2001
From: AceVest <zhaoyanbai@126.com>
Date: Wed, 3 Jul 2019 18:26:27 +0800
Subject: [PATCH] usart dma variable receive length

---
 learn/doc/mac_bash_profile |  2 +-
 learn/stm32/USART.md       | 89 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 90 insertions(+), 1 deletion(-)

diff --git a/learn/doc/mac_bash_profile b/learn/doc/mac_bash_profile
index 6d3c43c..835a2ef 100644
--- a/learn/doc/mac_bash_profile
+++ b/learn/doc/mac_bash_profile
@@ -26,7 +26,7 @@ CLOSECOLOR="\[\033[00m\]"
 
 #PS1='\[\033[02;37m\]\t\[\033[00m\]\[\033[01;37m\]@\[\033[01;33m\]\W\[\033[00m\]\$ '
 #PS1='\[\033[02;37m\]\t\[\033[00m\]\[\033[01;37m\]@\[\033[01;33m\]\W\[\033[00m\]\$ '
-PS1="$GRAY\t$CLOSECOLOR$WHITE@$PURPLE\h $CYAN\W$RED\$ $CLOSECOLOR"
+PS1="$RED\t$CLOSECOLOR$YELLOW@$PURPLE\h $CYAN\W$RED\$ $CLOSECOLOR"
 alias ll='ls -lGh'
 alias ls='ls -Gh'
 alias rm='rm -rf'
diff --git a/learn/stm32/USART.md b/learn/stm32/USART.md
index 094d22b..2fe1377 100644
--- a/learn/stm32/USART.md
+++ b/learn/stm32/USART.md
@@ -222,4 +222,93 @@ void USART2_IRQHandler(void)
   {
 	TransferUsartData();
   }
+```
+
+## USART DMA 任意字节接收
+需要把DMA接收模式改为`Circular`模式
+
+```
+#define BUFSZ	2
+typedef struct {
+	uint32_t len;
+	DMA_HandleTypeDef *dmarx;
+	uint8_t  buf[BUFSZ];
+}UsartDmaData_t;
+
+#define CBUFSIZE 512
+typedef struct CircleBuffer {
+	uint32_t rp;
+	uint32_t wp;
+	uint8_t  buf[CBUFSIZE]
+} CircleBuffer_t;
+
+UsartDmaData_t  usart1_dma_data;
+CircleBuffer_t circle_buf;
+
+static uint32_t tick = 0;
+void InitUsartDmaTransfer(){
+
+	__HAL_UART_ENABLE_IT(&huart1, UART_IT_IDLE);
+
+	memset(&usart1_dma_data, 0, sizeof(usart1_dma_data));
+	memset(&circle_buf, 0, sizeof(circle_buf));
+
+	usart1_dma_data.dmarx = &hdma_usart1_rx;
+
+	HAL_UART_Receive_DMA(&huart1, usart1_dma_data.buf, BUFSZ);
+
+	//HAL_Delay(1000);
+	HAL_UART_Transmit(&huart1, "AT+CIFSR\r\n", 10, 0xFFFF);
+}
+
+
+void TransferUsartData() {
+	if(circle_buf.rp == circle_buf.wp) {
+		HAL_Delay(10); // 很重要
+		return;
+	}
+
+	uint8_t t = circle_buf.buf[circle_buf.rp];
+	HAL_UART_Transmit(&huart1, &t, 1, 0xFFFF);
+	circle_buf.rp = (circle_buf.rp + 1) % CBUFSIZE;
+}
+
+void WriteCircleData(uint8_t *data, uint32_t size) {
+	for(uint32_t i=0; i<size; i++) {
+		if((circle_buf.wp + 1) % CBUFSIZE == circle_buf.rp) {
+			continue;
+		}
+
+		circle_buf.buf[circle_buf.wp] = data[i];
+
+		circle_buf.wp = (circle_buf.wp + 1) % CBUFSIZE;
+
+	}
+}
+
+
+static uint32_t cplt_cnt = 0;
+void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart) {
+	cplt_cnt++;
+	//HAL_UART_Transmit(huart, usart1_dma_data.buf, BUFSZ, 0xFFFF);
+	WriteCircleData(usart1_dma_data.buf, BUFSZ);
+}
+
+void ReceiveUsartData(UART_HandleTypeDef *huart) {
+	if(huart->Instance != USART1) {
+		return ;
+	}
+	uint32_t flag = __HAL_UART_GET_FLAG(huart,UART_FLAG_IDLE);
+	if(flag == RESET) {
+		return;
+	}
+
+	__HAL_UART_CLEAR_IDLEFLAG(huart);
+
+	HAL_UART_DMAStop(huart);
+
+	WriteCircleData(usart1_dma_data.buf, BUFSZ - usart1_dma_data.dmarx->Instance->CNDTR);
+
+	HAL_UART_Receive_DMA(&huart1, usart1_dma_data.buf, BUFSZ);
+}
 ```
\ No newline at end of file
-- 
2.44.0