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Table Of Contents
Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 376
UG585 (v1.11) September 27, 2016
Chapter 13: SD/SDIO Controller
13.3.6 External Interface Usage Example
Zynq-7000 devices provide two secure digital (SD) ports that support SD and SDIO devices (see
Figure 13-7).
13.3.7 Supported Configurations
The SD/SDIO controller supports operation in several configurations:
Secure digital (SD) memory
Secure digital input/output (SDIO)
Some SD card slots provide two additional pins: card detect (CDn) to signal the insertion or presence
of a card, and write protect (WP) to report the position of the write protect switch on the memory
card. These signals must be externally pulled up. The card normally pulls CDn Low when inserted. If
the WP switch is set to protect the card from writes, then the WP signal remains High. The wiring
schematic is shown in Figure 13-8. If the card does not function in this manner, then an alternate
method is required to signal the insertion or presence of the card. Additional board design
information is located in UG933
, Zynq-7000 All Programmable SoC PCB Design Guide.
Production versions of the BootROM do not look for CDn to be pulled Low; it assumes the card is
installed. Xilinx drivers require that these signals are routed through the MIO and function properly
to provide card state to the software. The routing is done using a slcr.SD{1,0}_WP_CD_SEL register.
X-Ref Target - Figure 13-7
Figure 13-7: SDIO Controller Device Wiring Diagram
Zynq Device
SDIO Device
CLK
CMD
DAT[3:0]
SDx_CLK
SDx_CMD
SDx_DAT[3:0]
SD/SDIO
Controller
UG595_c13_07_031812