K66用eDMA通过UART发送数据

fuqingxu · 发表于 2018-1-12 12:46:19

//作者：哈工大智能车创新俱乐部
////主要依赖：MK66F18.h(CMSIS Peripheral Access Layer for MK66F18)
////描述：用DMA发送数据，减缓CPU的运行压力。

#define BAUD_RATE 115200
#define UART_WITH_DMA uart1
#define DMA_UARTn_Tx DMA_UART1_Tx

#define DMA_CHANNEL_in_GROUP1 17 //请用16到31通道
//选group1 配置group1的优先级低于group 0（摄像头驱动使用g0）

#define default_transmittion_size 50
#define default_minor_loop_counter                   default_transmittion_size
#define default_dma_address_go_back_when_finish       default_transmittion_size

uint8 sendbuff[1024]="Empty eDMA-UART send buff,wanna put some thing in here?\n";
extern  UART_Type * uart[5];
void uart_init_with_dma()
{

  uart_init (UART_WITH_DMA, BAUD_RATE);
  uart[UART_WITH_DMA]->C2 |=
                  (0
                     | UART_C2_TE_MASK                      //发送使能
                     | UART_C2_RE_MASK                      //接收使能
                     | UART_C2_TIE_MASK                   //发送中断或DMA传输请求使能
                  );
  uart[UART_WITH_DMA]->C2 &=~UART_C2_TCIE_MASK;
  uart[UART_WITH_DMA]->C5 |=UART_C5_TDMAS_MASK;

  SIM->SCGC7 |= SIM_SCGC7_DMA_MASK;                      //时钟
  SIM->SCGC6 |= SIM_SCGC6_DMAMUX_MASK;                   //时钟
  DMAMUX0->CHCFG[DMA_CHANNEL_in_GROUP1] = (0
                        | DMAMUX_CHCFG_ENBL_MASK                   // Enable routing of DMA request
                        | DMAMUX_CHCFG_SOURCE(DMA_UARTn_Tx)  // 通道触发传输源:
                     );

  DMA0->CR  |= DMA_CR_GRP0PRI_MASK ;//CR_GRP0PRI=1    //设0组有高优先级
  DMA0->CR  &=~ DMA_CR_GRP1PRI_MASK ;//CR_GRP1PRI=0    //设1组有低优先级
  //实际上用DMA1，即16到31通道
  //PS：DMA0是0到15通道

  DMA0->TCD[DMA_CHANNEL_in_GROUP1].SADDR =(uint32)(void *)(sendbuff) ;
  DMA0->TCD[DMA_CHANNEL_in_GROUP1].DADDR =(uint32)(&(uart[UART_WITH_DMA]->D));

  DMA0->TCD[DMA_CHANNEL_in_GROUP1].NBYTES_MLNO = DMA_NBYTES_MLNO_NBYTES(1);////需要发送的数据，最好是4的整数倍.
  //UART准备好后触发一次minor loop  每个minor loop 只能把一个字节送入传输用的寄存器

  DMA0->TCD[DMA_CHANNEL_in_GROUP1].SLAST= - default_dma_address_go_back_when_finish;  ////大循环结束后，源地址改变量。最好是4的整数倍，等于上面
  DMA0->TCD[DMA_CHANNEL_in_GROUP1].DLAST_SGA = 0;                      ////大循环结束后，目标地址改变量。最好是4的整数倍，等于上面
  //UART情况地址不变

  DMA0->TCD[DMA_CHANNEL_in_GROUP1].SOFF = 1;             //读取一次地址后，偏移量，与DMA_ATTR_SSIZE有关？
  DMA0->TCD[DMA_CHANNEL_in_GROUP1].DOFF = 0;             //写一次地址后，  偏移量，与DMA_ATTR_DSIZE有关？

  DMA0->TCD[DMA_CHANNEL_in_GROUP1].ATTR = (
                                             DMA_ATTR_SSIZE(0)
                                          | DMA_ATTR_DSIZE(0)
                                          | DMA_ATTR_SMOD(0)             //Source address modulo feature is disabled
                                          | DMA_ATTR_DMOD(0)
                                          |0
                                       );

  DMA0->TCD[DMA_CHANNEL_in_GROUP1].CITER_ELINKNO = DMA_CITER_ELINKNO_CITER(default_minor_loop_counter);//minor loop小循环计数
  DMA0->TCD[DMA_CHANNEL_in_GROUP1].BITER_ELINKNO = DMA_BITER_ELINKNO_BITER(default_minor_loop_counter);//需要与上面的值实质相等
  DMA0->TCD[DMA_CHANNEL_in_GROUP1].CSR = 0;
  DMA0->TCD[DMA_CHANNEL_in_GROUP1].CSR = (0
                           | DMA_CSR_BWC(3)//带宽控制,每读一次，eDMA 引擎停止 8 个周期
                           //DMA冷却时间（0不停止；1保留；2停止4周期；3停止8周期）
//取消注释，解除反复发送    // | DMA_CSR_DREQ_MASK          //主循环结束后停止硬件请求  /* major_loop递减为0时自动关闭DMA，即只进行一次DMA传输 */
                           | DMA_CSR_INTMAJOR_MASK       //主循环结束后产生中断
                        );
  //DMA0->CR &= ~DMA_CR_EMLM_MASK;//Minor Loop Mapping Disabled.//default disabled already

// DMA0->TCD[DMA_CHANNEL_in_GROUP1].CSR |= DMA_CSR_START(1);
  DMA0->ERQ &=~ (DMA_ERQ_ERQ0_MASK<<( DMA_CHANNEL_in_GROUP1 ));

  uint8 test = DMA0->DCHPRI16;

}
/*
*说明：开始循环传输，开始之后不用管。。
*传输size个字节
*地址为上面的sendbuff[1024]
*/
void uart_dma_start_Nostop(uint32 size)
{
  DMA0->TCD[DMA_CHANNEL_in_GROUP1].CITER_ELINKNO = DMA_CITER_ELINKNO_CITER(size);//minor loop小循环计数
  DMA0->TCD[DMA_CHANNEL_in_GROUP1].BITER_ELINKNO = DMA_BITER_ELINKNO_BITER(size);//需要与上面的值实质相等
  DMA0->TCD[DMA_CHANNEL_in_GROUP1].SLAST= - size;  ////大循环结束后，源地址改变量
  DMA0-> ERQ |= (1 << DMA_CHANNEL_in_GROUP1);    //开始循环传输
}
/*
*说明：开始循环传输，开始之后不用管。。
*传输size个字节
*传输某地址开始的size个字节
*/
void uart_dma_start_Nostop_plus_BuffAddress(void *t,uint32 size)
{
  DMA0->TCD[DMA_CHANNEL_in_GROUP1].SADDR =(uint32)t;
  DMA0->TCD[DMA_CHANNEL_in_GROUP1].CITER_ELINKNO = DMA_CITER_ELINKNO_CITER(size);//minor loop小循环计数
  DMA0->TCD[DMA_CHANNEL_in_GROUP1].BITER_ELINKNO = DMA_BITER_ELINKNO_BITER(size);//需要与上面的值实质相等
  DMA0->TCD[DMA_CHANNEL_in_GROUP1].SLAST= - size;  ////大循环结束后，源地址改变量
  DMA0-> ERQ |= (1 << DMA_CHANNEL_in_GROUP1);    //开始循环传输
}

void uart_dma_stop()
{
DMA0->ERQ &=~ (DMA_ERQ_ERQ0_MASK<<( DMA_CHANNEL_in_GROUP1 ));
}

补充内容 (2018-7-18 23:30):
66