MCI Interface

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MCI Interface

2023-09-12 16:51| 来源: 网络整理| 查看: 265

Send Command to card and get the response.

Parameters [in]cmdMemory Card command [in]argCommand argument [in]flagsCommand flags [out]responsePointer to buffer for response ReturnsStatus Error Codes

The function ARM_MCI_SendCommand

sends commands to the memory card retrieve the response from the card optionally, start the data transfer.

The parameter cmd is the command sent to the card. The parameter arg contains arguments for the command cmd. The parameter flags controls the behavior of the operation and takes predefined values listed in the table below. The parameter response is a pointer to receive data.

The parameter flags can have the following values:

Parameter flags Description ARM_MCI_RESPONSE_NONE No response expected (default) ARM_MCI_RESPONSE_SHORT Short response (48-bit) expected ARM_MCI_RESPONSE_SHORT_BUSY Short response with busy signal (48-bit) expected ARM_MCI_RESPONSE_LONG Long response (136-bit) expected ARM_MCI_RESPONSE_INDEX Check command index in response ARM_MCI_RESPONSE_CRC Check CRC in response ARM_MCI_WAIT_BUSY Wait until busy before sending the command ARM_MCI_TRANSFER_DATA Activate Data transfer ARM_MCI_CARD_INITIALIZE Execute Memory Card initialization sequence ARM_MCI_INTERRUPT_COMMAND Send Interrupt command (CMD40 - MMC only) ARM_MCI_INTERRUPT_RESPONSE Send Interrupt response (CMD40 - MMC only) ARM_MCI_BOOT_OPERATION Execute Boot operation (MMC only) ARM_MCI_BOOT_ALTERNATIVE Execute Alternative Boot operation (MMC only) ARM_MCI_BOOT_ACK Expect Boot Acknowledge (MMC only) ARM_MCI_CCSD Send Command Completion Signal Disable (CCSD) for CE-ATA device ARM_MCI_CCS Expect Command Completion Signal (CCS) for CE-ATA device

Calling the function ARM_MCI_SendCommand only starts the operation. The function is non-blocking and returns as soon as the driver has started the operation. It is not allowed to call this function again until the operation is in progress.

After the command is sent the response is retrieved if specified with ARM_MCI_RESPONSE_xxx flags. When the command completes successfully (requested response is received without errors) the ARM_MCI_EVENT_COMMAND_COMPLETE event is generated. In case that response is requested but not received the ARM_MCI_EVENT_COMMAND_TIMEOUT event is generated instead. In case of invalid response (or CRC error) the ARM_MCI_EVENT_COMMAND_ERROR event is generated instead. Progress of command operation can be monitored by calling the ARM_MCI_GetStatus and checking the command_active flag.

After the command operation the data transfer operation is started if specified with ARM_MCI_TRANSFER_DATA flag. The data transfer needs to be configured before that by calling the ARM_MCI_SetupTransfer. When the data transfer completes successfully the ARM_MCI_EVENT_TRANSFER_COMPLETE event is generated. In case that data transfer is not completed in-time (specified by ARM_MCI_DATA_TIMEOUT) the ARM_MCI_EVENT_TRANSFER_TIMEOUT event is generated instead. In case of CRC errors the ARM_MCI_EVENT_TRANSFER_ERROR event is generated instead. Progress of data transfer operation can be monitored by calling the ARM_MCI_GetStatus and checking the transfer_active flag.

See also:

ARM_MCI_SignalEvent

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