Mmc_Dat Pullups; Mmc/Sd Internal Pullups - Texas Instruments OMAP5910 Technical Reference Manual

7.12.6 MMC/SD Internal Pullups

Table 7–92. MMC_CMD Pullups
MMC_SD Host
Controller Status
Input
Input
Output
Table 7–93. MMC_DAT Pullups
MMC_SD Host Controller Status
Input
Input
Output
There are internal pullups on the following pins:
-
MMC.CMD I/O pin
-
MMC.DAT[3:0] I/O pins
MMC cards work in open drain mode on the MMC.CMD line during the identifi-
cation phase, and more generally for broadcast MMC commands; con-
sequently, a pullup on the MMC.CMD line is needed.
When MMC.CMD and MMC.DAT[3:0] line work in push/pull mode, it is impor-
tant to prevent bus floating conditions. Consequently, pullups are needed.
These pullups are directly controlled by the MMC/SD host controller
(adp_rcmd_o and adp_rdat_o) and are only active when required, which
saves power.
Table 7–92 and Table 7–93 show activation conditions for the MMC.CMD and
MMC.DAT pullups.
MMC CARD Status
Input
Output
Input
MMC CARD Status
In flash-SPI mode, when no data is on the MMC.CMD and MMC.DAT lines
(input and output of the flash), the pullups are disabled.
MMC_CMD Pullup
(Open Drain Mode)
Active
Active
Disabled
Input
Output
Input
MPU Public Peripherals
MMC/SD Host Controller
MMC_CMD Pullup
(Push/Pull Mode)
Active
Disabled
Disabled
MMC_DAT Pullup (Both Modes)
Active
Disabled
Disabled
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