Page Comparison

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                                   FS_DEV_SD_CARD_CMD  *p_cmd,

                                   void                *p_src,

                                   FS_DEV_SD_CARD_ERR  *p_err);

File	Called from	Code enabled by
`fs_dev_sd_card_bsp.c`	`FSDev_SD_Card_WrData()`	N/A

Write data following a command.

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The implementation of FSDev_SD_Card_BSP_CmdDataWr() in Listing C-10 is is targeted for the same host controller as the other listings in this chapter; for more information, see FSDev_SD_Card_BSP_CmdStart().

Code Block

language	cpp
title	FSDev_SD_Card_BSP_CmdDataWr()

void  FSDev_SD_Card_BSP_CmdDataWr (FS_QTY               unit_nbr,
                                   FS_DEV_SD_CARD_CMD  *p_cmd,
                                   void                *p_src,
                                   FS_DEV_SD_CARD_ERR  *p_err)
{
    CPU_INT16U  interrupt_status;
    CPU_INT16U  error_status;
    CPU_INT16U  timeout;
    timeout          = 0u;                        /* Wait until data xfer compl. */  (1)
    interrupt_status = REG_INTERRUPT_STATUS;
    while (DEF_BIT_IS_CLR(interrupt_status,BIT_INTERRUPT_STATUS_ERROR | 
                                           BIT_INTERRUPT_STATUS_TRANSFER_COMPLETE) == DEF_YES)) {
        timeout++;
        interrupt_status = REG_INTERRUPT_STATUS;
        if (timeout == TIMEOUT_TRANSFER_MAX) {
           *p_err = FS_DEV_SD_CARD_ERR_WAIT_TIMEOUT;
            return;
        }
    }
                                                  /* Handle error.              */  (2)
    if (DEF_BIT_IS_SET(interrupt_status, BIT_INTERRUPT_STATUS_ERROR) == DEF_YES) {
        error_status = REG_ERROR_STATUS;
        if (DEF_BIT_IS_SET(error_status, REG_ERROR_STATUS_DATA_END_BIT) == DEF_YES) {
           *p_err = FS_DEV_SD_CARD_ERR_DATA;
        } else if (DEF_BIT_IS_SET(error_status, REG_ERROR_STATUS_DATA_CRC) == DEF_YES) {
           *p_err = FS_DEV_SD_CARD_ERR_DATA_CRC;
        } else if (DEF_BIT_IS_SET(error_status, REG_ERROR_STATUS_DATA_TIMEOUT) == DEF_YES) {
           *p_err = FS_DEV_SD_CARD_ERR_DATA_TIMEOUT;
        } else {
           *p_err = FS_DEV_SD_CARD_ERR_UNKONWN;
        }
        REG_ERROR_STATUS     = error_status;
        REG_INTERRUPT_STATUS = interrupt_status;
        return;
    }
   
   *p_err = FS_DEV_SD_CARD_ERR_NONE;                                                  (3)
}

Panel

bgColor	#f0f0f0

(1) Wait until data transfer completes or an error occurs. The wait loop (or wait on semaphore) SHOULD always have a timeout to avoid blocking the task in the case of an unforeseen hardware malfunction or a software flaw.

(2) Check if an error occurred. The error status register is decoded to produce the actual error condition. That is not necessary, strictly, but error counters that accumulate within the generic driver based upon returned error values may be useful while debugging a port.

(3) Return no error. The data has been transferred already from the memory buffer using DMA.

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