Mmc Protocol Layout Notes; Signals ............................................................................................Ii: - Intel PXA27 Series Design Manual

MultiMediaCard/SD/SDIO Card Controller
See Figure 15-2
Card controller and an MMC device socket.
Figure 15-2. MMC Protocol Interface Schematic Diagram
MMDAT<0>
MMCL
MMCM
D
MMCCS<x>
15.4.1.3

MMC Protocol Layout Notes

See Table 15-5
to their respective specifications.
Table 15-5. MMC Pull-up and Pull-down Resistors
Signal
MMCMD
MMDAT<0>
The 0.1 µF capacitor (C1) shown in
the MMC socket pin 3 (VDD) and pin 4 (VSS1).
The MMC socket is not equipped with a mechanical card detect switch; therefore, other measures
must be taken to produce a card detect. Use an SD/SDIO Card socket if a card detect and write
protection signal are desired even if only MMC devices are being used. The example circuit shown
in Figure 15-4
MMDAT<2> are not used as the MMC device does not have physical contacts to interface to these
SD/SDIO Card socket signals.
II:15-6
for the detailed schematic diagram of the interface between the MMC/SD/SDIO
K
for the list of pull-up and pull-down resistors required for MMC devices according
Pull-up or Pull-down
pull-up
pull-up
Figure 15-2
supports using an MMC device with an SD/SDIO Card socket; MMDAT<1> and
3.3V
R2
51K
7
6
5
3.3V
3.3V
4
C1
R1
0.1
3
10K
uF
2
1
Min Max
4.7 K Ω 100 K Ω
Prevents bus floating
50 K Ω 100 K Ω
Prevents bus floating
must be located within 0.512 inches (13 mm) of
®
Intel PXA27x Processor Family Design Guide
MMC
DAT
Socket
VSS2
CLK
VDD
VSS1
CMD
Chip Select (SPI Mode)
MMC_006_P2
Remark