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MMC/SD/SDIO Use Cases and Tips
6. MMCHS controller pre-card identification configuration.
For more information about different steps the MMCHS controller goes through during initial configuration
see
, MMC/SD/SDIO Basic Programming Model.
24.6.1.3.1.1 MMCHS Controller Interface and Functional Clocks Enabling
To enable the interface and functional clocks of the MMCHS1 controller, the following steps must be done:
1. Enable the interface clock for the MMCHS1 controller (set the PRCM.CM_ICLKEN1_CORE[24]
EN_MMCHS1).
2. Enable the functional clock for the MMCHS1 module (set the PRCM.CM_FCLKEN1_CORE[24]
EN_MMCHS1).
shows all PRCM registers to be configured to enable interface and functional clocks for
MMCHS1 controller.
Table 24-8. Register Print for the MMCHS1 Controller Clock Initialization
Register Name
Register Address
Value
Value Description
PRCM.CM_ICLKEN1_CORE
0x4800 4A10
0x01000000
MMCHS1 interface clock enabled
PRCM.CM_FCLKEN1_CORE
0x4800 4A00
0x01000000
MMCHS1 functional clock enabled
24.6.1.3.1.2 MMCHS Controller Software Reset
To software-reset the MMCHS1 controller, the following steps must be performed:
1. Write 0x2 in MMCHS1.
register.
2. Wait until MMCHS1.
[0] RESETDONE turns 1.
describes the software-reset registers.
Table 24-9. Software-Reset Register Description
Register Name
Register Address
Value
Value Description
MMCHS1.
0x4809 C010
0x00000002
Activate software reset
MMCHS1.
0x4809 C014
0x00000001
Reset is over.
24.6.1.3.1.3 MMCHS Controller Voltage Capabilities Initialization
MMCHS1 controller's voltage capabilities should be set in MMCHS1.
. See
.
Table 24-10. MMCHS Controller Voltage Capabilities Initialization
Register Name
Register Address
Value
Value Description
MMCHS1.
0x4809 C140
current_value | 0x06000000 Activate VS18 and VS30 in
register.
24.6.1.3.1.4 MMCHS Controller Default Initialization
Before sending any command, the MMCHS controller is configured with default values :
1. Default voltage support is set to 1.8 v in MMCHS1.
[11:9] SDVS.
2. MMC bus is set to open drain in MMCHS1.
[0] OD.
3. MMC data bus width is set to 1 in MMCHS1.
[1] DTW.
4. MMC Card's power is off.
5. MMC Card's clock is on in MMCHS1.
[2]
CEN.
6. MMCHS controller bus power up in MMCHS1.
[8] SDBP.
7. MMC card's clock frequency is set to 150 kHz in MMCHS1.
[15:6] CLKD.
shows the values that should be written in the right register pool.
3415
SWPU177N – December 2009 – Revised November 2010
MMC/SD/SDIO Card Interface
Copyright © 2009–2010, Texas Instruments Incorporated