串口接收DMA方式，先进入串口中断判断帧头，再进入DMA，结果DMA接收的第一位老出错？

jimmyningwang

串口接收DMA方式，先进入串口中断判断帧头，再进入DMA，结果DMA接收的第一位老出错？
求救原子哥

jimmyningwang

问题解决了，串口接收中断了打开DMA后会把当前的值传到内存中的，而不是等到下一个值来了再传到内存中，比设想的多了一个值，所以才会出现那样的循环

jimmyningwang

[mw_shl_code=c,true]#if EN_USART1_RX //?????????????? void USART1_IRQHandler(void) //?®??1????·??????ò { u8 Res; if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET) //???????? { Res = USART_ReceiveData(USART1);//(USART1->DR); //???????????????? ????×??? 0xbd 0xdb USART_RX_BUF[USART_RX_STA]=Res ; USART_RX_STA++; if(USART_RX_STA == 2) { USART_RX_STA = 0; if((USART_RX_BUF[0] == 0xbd)&&(USART_RX_BUF[1] == 0xdb)) { MYDMA_Enable(); //?ò??DMA???? } else {} } } } #endif [/mw_shl_code]

[mw_shl_code=c,true]#include "dma.h" u8 ReceiveBuff[32]; u16 Roll ; u16 Pitch ; u16 Yaw; u16 sign; float ROLL_N ; float PITCH_N ; float YAW_N ; float volt3n ; DMA_InitTypeDef DMA_InitStructure; NVIC_InitTypeDef NVIC_InitStructure; u16 DMA1_MEM_LEN;//±???DMA???????????????¤?? //DMA1???÷?¨?????? //???????????????????¨??,???????ù?????????é???????? //?????è->?????÷???? /8???????í?? /?????÷???????? //DMA?¨??DMA1_Channel5 ?®???????¨?? //cpar:???è???· //cmar:?????÷???· //cndtr:?????????? void MYDMA_Config(u32 cpar,u32 cmar,u16 cndtr) { RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); //????DMA???? //NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1); NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel5_IRQn; //?????????? NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); DMA_DeInit(DMA1_Channel5); //??DMA???¨??5?????÷???è???±???? DMA1_MEM_LEN=cndtr; DMA_InitStructure.DMA_PeripheralBaseAddr = cpar; //DMA???èUSART_RX?ù???· DMA_InitStructure.DMA_MemoryBaseAddr = cmar; //DMA?????ù???· DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC; //????????·??ò???????è????·????????? DMA_InitStructure.DMA_BufferSize = cndtr; //DMA?¨????DMA???????ó?? DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; //???è???·?????÷??±? DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; //???????·?????÷???? DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte; //?????í????8?? DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte; //?????í????8?? DMA_InitStructure.DMA_Mode = DMA_Mode_Normal; //?¤×÷?????????????? DMA_InitStructure.DMA_Priority = DMA_Priority_Medium; //DMA?¨?? x???????????? DMA_InitStructure.DMA_M2M = DMA_M2M_Disable; //DMA?¨??x?????è?????????????????? DMA_Init(DMA1_Channel5, &DMA_InitStructure); //?ù??DMA_InitStruct?????¨????????????DMA???¨??USART1_Tx_DMA_Channel?ù±ê?????????÷ DMA_ITConfig(DMA1_Channel5,DMA_IT_TC,ENABLE);//????DMA?????ê?ú?ú???? } //????????DMA???? void MYDMA_Enable(void) { DMA_Cmd(DMA1_Channel5, DISABLE ); //??±?USART1 TX DMA1 ?ù???????¨?? DMA_SetCurrDataCounter(DMA1_Channel5,DMA1_MEM_LEN);//DMA?¨????DMA???????ó?? 32Bit DMA_Cmd(DMA1_Channel5, ENABLE); //????USART1 RX DMA1 ?ù???????¨?? } [/mw_shl_code]

附上串口接收中断和DMA配置函数

jimmyningwang

 现在的问题是，帧头在串口中断里能收到，0xbd 和0xdb，DMA里接收的数据第一位是一帧数据的最后一位，从第二位开始才是正确的顺序，第二次接收串口还是帧头在串口中断里能收到，0xbd 和0xdb，DMA里接收的数据是从倒数第三位开始，然后从第四位才是正确的数据
要发的数据：bd db  04 0e 00 07 00 23 02 5d 01 00 f0 04 00 f9 ff f7 ff 00 00 f8 ff 5b f5 ed 1b a3 26 00 00 7b 24 00
第一次收到：bd db  00 04 0e 00 07 00 23 02 5d 01 00 f0 04 00 f9 ff f7 ff 00 00 f8 ff 5b f5 ed 1b a3 26 00 00 7b 24
第二次收到：bd db 7b 24 00  04 0e 00 07 00 23 02 5d 01 00 f0 04 00 f9 ff f7 ff 00 00 f8 ff 5b f5 ed 1b a3 26 00 00
第三次收到：bd db 00 00 7b 24 00  04 0e 00 07 00 23 02 5d 01 00 f0 04 00 f9 ff f7 ff 00 00 f8 ff 5b f5 ed 1b a3 26
。。。
其中bd db是串口中断里接收的，后面是DMA里接收的

正点原子

帮顶。。。。