MCI Bus Data WidthMCI Control Codes

Specify the data bus width.

Macros

#define ARM_MCI_BUS_DATA_WIDTH_1   (0x00)
 Bus data width: 1 bit (default)
 
#define ARM_MCI_BUS_DATA_WIDTH_4   (0x01)
 Bus data width: 4 bits.
 
#define ARM_MCI_BUS_DATA_WIDTH_8   (0x02)
 Bus data width: 8 bits.
 
#define ARM_MCI_BUS_DATA_WIDTH_4_DDR   (0x03)
 Bus data width: 4 bits, DDR (Dual Data Rate) - MMC only.
 
#define ARM_MCI_BUS_DATA_WIDTH_8_DDR   (0x04)
 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

#define ARM_MCI_BUS_DATA_WIDTH_1   (0x00)

Bus data width: 1 bit (default)

#define ARM_MCI_BUS_DATA_WIDTH_4   (0x01)

Bus data width: 4 bits.

#define ARM_MCI_BUS_DATA_WIDTH_8   (0x02)

Bus data width: 8 bits.

#define ARM_MCI_BUS_DATA_WIDTH_4_DDR   (0x03)

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

#define ARM_MCI_BUS_DATA_WIDTH_8_DDR   (0x04)

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