STW4811MBRASLASHLF datasheet(55/86 Pages) STMICROELECTRONICS

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Functional description

STw4811M/STw4811N

54/85

4.5

SD/MMC/SDIO module

Figure 14.

SD/MMC/SDIO block diagram

4.5.1

SD/MMC/SDIO LDO supply

The Vmmc LDO is supplied via the input Vbat_Vmmc. According to the protection diode

design, the voltage on this input pin Vbat_Vmmc must be always higher or equal to the

battery voltage.

Vbat_Vmmc >= Vbat

By programming ‘vmmc_sel[2:0] bits of

configuration 1 register (Table 18), this LDO

provides the power supply (1.8 V, 1.85 V, 2.6 V, 2.7 V, 2.85 V, 3 V, 3.3 V) with a 150 mA

current compliance for any of the following peripherals.

●

SD card

●

MMC card

●

SDIO card

If an application does not request to use the level shifter feature, this LDO can be used to

supply an other peripheral, in this case, to reduce the internal current consumption due to

level shifter it is recommended to set to “1” ‘mmc_ls_status’ bit of

configuration 1 register

(

Table 18).

If an application, like HDD, requests more than 150 mA current supply and the use of the

internal level shifters, internal LDO must be disabled.

The application will be supplied by an external LDO and internal level shifter will be directly

supplied by the external LDO.

In this configuration, ‘pdn_vmmc’ bit is set to “0”, ‘mmc_ls_status’ is set to “0” (

Table 18) and

‘external_vmmc’ bit is set to “1” (

Table 28).

SD/ MMC/SDIO interface

LDO

VBAT_VMMC

VMMC

Driver

Level

shifter

LATCHCLK

CLKOUT

DATAOUT0

MCCLK

MCFBCLK

MCCMDDIR

MCDATA0DIR

MCDATA31DIR

MCCMD

MCDATA[3:1]

MCDATA0

SD, MMC

SDIO OR

cards

CMDOUT

5*RB

DATAOUT[3:1]

VIO_VMEM

EMIF

MCDATA2DIR

3*RA

150 mA

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