Omap5910 Mmc/Sd Pin Multiplexing - Texas Instruments OMAP5910 Technical Reference Manual

Configuration Module
Table 6–25. Functional Pin Multiplexing Control Register 3
(FUNC_MUX_CTRL3...FUNC_MUX_CTRLD)
6.7.4

OMAP5910 MMC/SD Pin Multiplexing

6.7.5 OMAP5910 Pullups and Pulldowns
6-26
FUNC_MUX_CTRL(2:0)
Register Value
000
001
010
011
100
101
110
111
For a given interface, the value of the FUNC_MUX_CTRL(2:0) register can
vary from pin to pin. For example, the USB1_HOST port is split between func-
tional multiplexing 2 and functional multiplexing three modes in Appendix A,
Input/Output Descriptions. In this case four of the FUNC_MUX_
CTRL(2:0) registers
FUNC_MUX_CTRL(2:0) registers have a value of 010.
The enabling of the MMC/SD function on the device's pins is a special case
on the OMAP5910 device. The MMC/SD pin interface uses the state of a
device pin (STAT_VAL/WKUP) at release of power-on reset to determine if the
MMC/SD function is enabled at the device's pins. The power-on reset sam-
pling of a high level on this pin forces the device's I/O into a state that is consis-
tent with MMC/SD. This means that several pullups are enabled when in MMC/
SD mode. Users must program the OMAP5910 configuration registers to set
up the proper functional multiplexing modes. Users of 4-bit MMC/sd must be
particularly aware that the CONF_MOD_MSMMC_VSS_HIZ_OVERRIDE bit
in the MOD_CONF_CTRL_0 register must be programmed to a 1 to enable
the use of the MMC.DAT2 device pin. For further details on the MMC/SD
pin multiplexing on the OMAP5910 device, see Appendix A, Input/Output
Descriptions, and Section 7.12, MMC/SD Host Controller.
The OMAP5910 device implements both pullups and pulldowns on several
I/Os. In this document there are several references to pulldowns and pulldown
enables. It is proper to assume that if an OMAP5910 device pin has a pullup,
the corresponding pulldown enables (enables = 0/disables = 1) the pullup.
Corresponding Functional Modes
Default configuration/functional multiplexing 0
Functional multiplexing 1
Functional multiplexing 2
Functional multiplexing 3
Functional multiplexing 4 (Reserved)
Functional multiplexing 5 (Reserved)
Functional multiplexing 6 (Reserved)
Functional multiplexing 7 (Reserved)
has a value of 001 and the other four