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

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Macros
MCI Bus Speed Mode
MCI Interface » MCI Control Codes

Specify the bus speed mode. More...

## Macros
#define | ARM_MCI_BUS_DEFAULT_SPEED (0x00UL)
| SD/MMC: Default Speed mode up to 25/26MHz.
#define | ARM_MCI_BUS_HIGH_SPEED (0x01UL)
| SD/MMC: High Speed mode up to 50/52MHz.
#define | ARM_MCI_BUS_UHS_SDR12 (0x02UL)
| SD: SDR12 (Single Data Rate) up to 25MHz, 12.5MB/s: UHS-I (Ultra High Speed) 1.8V signaling.
#define | ARM_MCI_BUS_UHS_SDR25 (0x03UL)
| SD: SDR25 (Single Data Rate) up to 50MHz, 25 MB/s: UHS-I (Ultra High Speed) 1.8V signaling.
#define | ARM_MCI_BUS_UHS_SDR50 (0x04UL)
| SD: SDR50 (Single Data Rate) up to 100MHz, 50 MB/s: UHS-I (Ultra High Speed) 1.8V signaling.
#define | ARM_MCI_BUS_UHS_SDR104 (0x05UL)
| SD: SDR104 (Single Data Rate) up to 208MHz, 104 MB/s: UHS-I (Ultra High Speed) 1.8V signaling.
#define | ARM_MCI_BUS_UHS_DDR50 (0x06UL)
| SD: DDR50 (Dual Data Rate) up to 50MHz, 50 MB/s: UHS-I (Ultra High Speed) 1.8V signaling.

## Description

Specify the bus speed mode.

The function ARM_MCI_Control with control = ARM_MCI_BUS_SPEED configures the bus speed of the MCI to the requested bits/s specified with arg.

The function ARM_MCI_Control with control = ARM_MCI_BUS_SPEED_MODE configures the bus speed mode of the MCI as specified with arg listed bellow.

The function ARM_MCI_GetCapabilities lists the supported bus speed modes. Initially, all SD cards use a 3.3 volt electrical interface. Some SD cards can switch to 1.8 volt operation. For example, the use of ultra-high-speed (UHS) SD cards requires 1.8 volt operation and a 4-bit bus data width. The data field uhs_signaling of the structure ARM_MCI_CAPABILITIES encodes whether the driver supports 1.8 volt UHS signaling.

See also
  - MCI Driver Strength

The following codes are defined:

## Macro Definition Documentation

## ◆ ARM_MCI_BUS_DEFAULT_SPEED

#define ARM_MCI_BUS_DEFAULT_SPEED (0x00UL)

SD/MMC: Default Speed mode up to 25/26MHz.

## ◆ ARM_MCI_BUS_HIGH_SPEED

#define ARM_MCI_BUS_HIGH_SPEED (0x01UL)

SD/MMC: High Speed mode up to 50/52MHz.

## ◆ ARM_MCI_BUS_UHS_SDR12

#define ARM_MCI_BUS_UHS_SDR12 (0x02UL)

SD: SDR12 (Single Data Rate) up to 25MHz, 12.5MB/s: UHS-I (Ultra High Speed) 1.8V signaling.

## ◆ ARM_MCI_BUS_UHS_SDR25

#define ARM_MCI_BUS_UHS_SDR25 (0x03UL)

SD: SDR25 (Single Data Rate) up to 50MHz, 25 MB/s: UHS-I (Ultra High Speed) 1.8V signaling.

## ◆ ARM_MCI_BUS_UHS_SDR50

#define ARM_MCI_BUS_UHS_SDR50 (0x04UL)

SD: SDR50 (Single Data Rate) up to 100MHz, 50 MB/s: UHS-I (Ultra High Speed) 1.8V signaling.

## ◆ ARM_MCI_BUS_UHS_SDR104

#define ARM_MCI_BUS_UHS_SDR104 (0x05UL)

SD: SDR104 (Single Data Rate) up to 208MHz, 104 MB/s: UHS-I (Ultra High Speed) 1.8V signaling.

## ◆ ARM_MCI_BUS_UHS_DDR50

#define ARM_MCI_BUS_UHS_DDR50 (0x06UL)

SD: DDR50 (Dual Data Rate) up to 50MHz, 50 MB/s: UHS-I (Ultra High Speed) 1.8V signaling.