| CMSIS-Driver Peripheral Interface for Middleware and Application Code |

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Macros
MCI Bus Data Width
MCI Interface » MCI Control Codes

Specify the data bus width. More...

## Macros
#define | ARM_MCI_BUS_DATA_WIDTH_1 (0x00UL)
| Bus data width: 1 bit (default)
#define | ARM_MCI_BUS_DATA_WIDTH_4 (0x01UL)
| Bus data width: 4 bits.
#define | ARM_MCI_BUS_DATA_WIDTH_8 (0x02UL)
| Bus data width: 8 bits.
#define | ARM_MCI_BUS_DATA_WIDTH_4_DDR (0x03UL)
| Bus data width: 4 bits, DDR (Dual Data Rate) - MMC only.
#define | ARM_MCI_BUS_DATA_WIDTH_8_DDR (0x04UL)
| Bus data width: 8 bits, DDR (Dual Data Rate) - MMC only.

## Description

Specify the data bus width.

The function ARM_MCI_Control with control = ARM_MCI_BUS_DATA_WIDTH specifies with arg the number of data I/O pins on the SD/MMC interface.

For high-speed memory cards, a 4-bit bus data width should be used (or 8-bit for eMMC). The data fields data_width_4 and data_width_8 of the structure ARM_MCI_CAPABILITIES encode whether the driver supports a specific bus data with.

The following codes are defined:

## Macro Definition Documentation

## ◆ ARM_MCI_BUS_DATA_WIDTH_1

#define ARM_MCI_BUS_DATA_WIDTH_1 (0x00UL)

Bus data width: 1 bit (default)

## ◆ ARM_MCI_BUS_DATA_WIDTH_4

#define ARM_MCI_BUS_DATA_WIDTH_4 (0x01UL)

Bus data width: 4 bits.

## ◆ ARM_MCI_BUS_DATA_WIDTH_8

#define ARM_MCI_BUS_DATA_WIDTH_8 (0x02UL)

Bus data width: 8 bits.

## ◆ ARM_MCI_BUS_DATA_WIDTH_4_DDR

#define ARM_MCI_BUS_DATA_WIDTH_4_DDR (0x03UL)

Bus data width: 4 bits, DDR (Dual Data Rate) - MMC only.

## ◆ ARM_MCI_BUS_DATA_WIDTH_8_DDR

#define ARM_MCI_BUS_DATA_WIDTH_8_DDR (0x04UL)

Bus data width: 8 bits, DDR (Dual Data Rate) - MMC only.