z-stack协议uart分析(DMA)

1、从ZMain里面的main函数开始分析

2、进入int main( void );

HalDriverInit();   //硬件相关初始化，有DMA初始化和UART初始化

3、进入HalDriverInit();

/* DMA */
#if (defined HAL_DMA) && (HAL_DMA == TRUE)   
// Must be called before the init call to any module that uses DMA.
HalDmaInit();
#endif

/* UART */
#if (defined HAL_UART) && (HAL_UART == TRUE)   // HAL_UART已经在IAR里面定义了HAL_UART=TRUE
HalUARTInit();
#endif

4、进入HalUARTInit();

#if HAL_UART_DMA     // HAL_UART_DMA已经在hal_board_cfg.h里面定义了HAL_UART_DMA     #define HAL_UART_DMA  1 
HalUARTInitDMA();
#endif

5、进入HalUARTInitDMA();配置引脚功能和DMA通道等

 /******************************************************************************
  * @fn      HalUARTInitDMA
  *
  * @brief   Initialize the UART
  *
  * @param   none
  *
  * @return  none
  *****************************************************************************/
 static void HalUARTInitDMA(void)
 {
   halDMADesc_t *ch;

   P2DIR &= ~P2DIR_PRIPO;
   P2DIR |= HAL_UART_PRIPO;

 #if (HAL_UART_DMA == 1)
   PERCFG &= ~HAL_UART_PERCFG_BIT;    // Set UART0 I/O to Alt. 1 location on P0.
 #else
   PERCFG |= HAL_UART_PERCFG_BIT;     // Set UART1 I/O to Alt. 2 location on P1.
 #endif
   PxSEL  |= UxRX_TX;                 // Enable Tx and Rx peripheral functions on pins.
   ADCCFG &= ~UxRX_TX;                // Make sure ADC doesnt use this.
   UxCSR = CSR_MODE;                  // Mode is UART Mode.
   UxUCR = UCR_FLUSH;                 // Flush it.

   // Setup Tx by DMA.
   ch = HAL_DMA_GET_DESC1234( HAL_DMA_CH_TX );

   // The start address of the destination.
   HAL_DMA_SET_DEST( ch, DMA_UDBUF );

   // Using the length field to determine how many bytes to transfer.
   HAL_DMA_SET_VLEN( ch, HAL_DMA_VLEN_USE_LEN );

   // One byte is transferred each time.
   HAL_DMA_SET_WORD_SIZE( ch, HAL_DMA_WORDSIZE_BYTE );

   // The bytes are transferred 1-by-1 on Tx Complete trigger.
   HAL_DMA_SET_TRIG_MODE( ch, HAL_DMA_TMODE_SINGLE );
   HAL_DMA_SET_TRIG_SRC( ch, DMATRIG_TX );

   // The source address is incremented by 1 byte after each transfer.
   HAL_DMA_SET_SRC_INC( ch, HAL_DMA_SRCINC_1 );

   // The destination address is constant - the Tx Data Buffer.
   HAL_DMA_SET_DST_INC( ch, HAL_DMA_DSTINC_0 );

   // The DMA Tx done is serviced by ISR in order to maintain full thruput.
   HAL_DMA_SET_IRQ( ch, HAL_DMA_IRQMASK_ENABLE );

   // Xfer all 8 bits of a byte xfer.
   HAL_DMA_SET_M8( ch, HAL_DMA_M8_USE_8_BITS );

   // DMA has highest priority for memory access.
   HAL_DMA_SET_PRIORITY( ch, HAL_DMA_PRI_HIGH );

   // Setup Rx by DMA.
   ch = HAL_DMA_GET_DESC1234( HAL_DMA_CH_RX );

   // The start address of the source.
   HAL_DMA_SET_SOURCE( ch, DMA_UDBUF );

   // Using the length field to determine how many bytes to transfer.
   HAL_DMA_SET_VLEN( ch, HAL_DMA_VLEN_USE_LEN );

   /* The trick is to cfg DMA to xfer 2 bytes for every 1 byte of Rx.
    * The byte after the Rx Data Buffer is the Baud Cfg Register,
    * which always has a known value. So init Rx buffer to inverse of that
    * known value. DMA word xfer will flip the bytes, so every valid Rx byte
    * in the Rx buffer will be preceded by a DMA_PAD char equal to the
    * Baud Cfg Register value.
    */
   HAL_DMA_SET_WORD_SIZE( ch, HAL_DMA_WORDSIZE_WORD );

   // The bytes are transferred 1-by-1 on Rx Complete trigger.
   HAL_DMA_SET_TRIG_MODE( ch, HAL_DMA_TMODE_SINGLE_REPEATED );
   HAL_DMA_SET_TRIG_SRC( ch, DMATRIG_RX );

   // The source address is constant - the Rx Data Buffer.
   HAL_DMA_SET_SRC_INC( ch, HAL_DMA_SRCINC_0 );

   // The destination address is incremented by 1 word after each transfer.
   HAL_DMA_SET_DST_INC( ch, HAL_DMA_DSTINC_1 );
   HAL_DMA_SET_DEST( ch, dmaCfg.rxBuf );
   HAL_DMA_SET_LEN( ch, HAL_UART_DMA_RX_MAX );

   // The DMA is to be polled and shall not issue an IRQ upon completion.
   HAL_DMA_SET_IRQ( ch, HAL_DMA_IRQMASK_DISABLE );

   // Xfer all 8 bits of a byte xfer.
   HAL_DMA_SET_M8( ch, HAL_DMA_M8_USE_8_BITS );

   // DMA has highest priority for memory access.
   HAL_DMA_SET_PRIORITY( ch, HAL_DMA_PRI_HIGH );
 }

6、紧接着需要配置串口

uartConfig.configured = TRUE; // 2x30 don't care - see uart driver.
uartConfig.baudRate = SERIAL_APP_BAUD;
uartConfig.flowControl = FALSE;
uartConfig.flowControlThreshold = SERIAL_APP_THRESH; // 2x30 don't care - see uart driver.
uartConfig.rx.maxBufSize = SERIAL_APP_RX_SZ; // 2x30 don't care - see uart driver.
uartConfig.tx.maxBufSize = SERIAL_APP_TX_SZ; // 2x30 don't care - see uart driver.
uartConfig.idleTimeout = SERIAL_APP_IDLE; // 2x30 don't care - see uart driver.
uartConfig.intEnable = TRUE; // 2x30 don't care - see uart driver.
uartConfig.callBackFunc = SerialApp_CallBack;
HalUARTOpen (UART0, &uartConfig);

7、进入HalUARTOpen (UART0, &uartConfig);

#if (HAL_UART_DMA == 1)
if (port == HAL_UART_PORT_0) HalUARTOpenDMA(config);
#endif

8、进入HalUARTOpenDMA(config);

 /******************************************************************************
  * @fn      HalUARTOpenDMA
  *
  * @brief   Open a port according tp the configuration specified by parameter.
  *
  * @param   config - contains configuration information
  *
  * @return  none
  *****************************************************************************/
 static void HalUARTOpenDMA(halUARTCfg_t *config)
 {
   dmaCfg.uartCB = config->callBackFunc;
   // Only supporting subset of baudrate for code size - other is possible.
   HAL_UART_ASSERT((config->baudRate == HAL_UART_BR_9600) ||
                   (config->baudRate == HAL_UART_BR_19200) ||
                   (config->baudRate == HAL_UART_BR_38400) ||
                   (config->baudRate == HAL_UART_BR_57600) ||
                   (config->baudRate == HAL_UART_BR_115200));

   if (config->baudRate == HAL_UART_BR_57600 ||
       config->baudRate == HAL_UART_BR_115200)
   {
     UxBAUD = ;
   }
   else
   {
     UxBAUD = ;
   }

   switch (config->baudRate)
   {
     case HAL_UART_BR_9600:
       UxGCR = ;
       dmaCfg.txTick = ; // (32768Hz / (9600bps / 10 bits))
                           // 10 bits include start and stop bits.
       break;
     case HAL_UART_BR_19200:
       UxGCR = ;
       dmaCfg.txTick = ;
       break;
     case HAL_UART_BR_38400:
       UxGCR = ;
       dmaCfg.txTick = ;
       break;
     case HAL_UART_BR_57600:
       UxGCR = ;
       dmaCfg.txTick = ;
       break;
     default:
       // HAL_UART_BR_115200
       UxGCR = ;
       dmaCfg.txTick = ;
       break;
   }

   // 8 bits/char; no parity; 1 stop bit; stop bit hi.
   if (config->flowControl)
   {
     UxUCR = UCR_FLOW | UCR_STOP;
     PxSEL |= HAL_UART_Px_CTS;
     // DMA Rx is always on (self-resetting). So flow must be controlled by the S/W polling the Rx
     // buffer level. Start by allowing flow.
     PxOUT &= ~HAL_UART_Px_RTS;
     PxDIR |=  HAL_UART_Px_RTS;
   }
   else
   {
     UxUCR = UCR_STOP;
   }

   dmaCfg.rxBuf[] = *(volatile uint8 *)DMA_UDBUF;  // Clear the DMA Rx trigger.
   HAL_DMA_CLEAR_IRQ(HAL_DMA_CH_RX);
   HAL_DMA_ARM_CH(HAL_DMA_CH_RX);
   osal_memset(dmaCfg.rxBuf, (DMA_PAD ^ 0xFF), HAL_UART_DMA_RX_MAX*);

   UxCSR |= CSR_RE;
   UxDBUF = ;  // Prime the DMA-ISR pump.

   // Initialize that TX DMA is not pending
   dmaCfg.txDMAPending = FALSE;
   dmaCfg.txShdwValid = FALSE;
 }

9、至此就可以正常使用该串口了，但是具体如何调用呢，有如下函数