ZYBO™ FPGA Board Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page
14
of
26
Zynq-7
MIO43
SD MICRO
DAT2
DAT3
CMD
VDD
CLK
GND
DAT0
3.3V
MIO42
MIO40
MIO41
MIO45
MIO44
DAT1
CD
TXS02612RTWR
Voltage Level Translator
MIO47
SD_D1
SD_D0
SD_CCLK
SD_CMD
SD_D3
SD_D2
1.8V
Figure 6. MicroSD slot signals.
Both low speed and high speed cards are supported, the maximum clock frequency being 50 MHz. A Class 4 card or
better is recommended.
Refer to section 3.1 for information on how to boot from an SD card. For more information, consult the Xilinx Zynq
TRM (ug585).
8
USB OTG
The ZYBO implements one of the two available PS USB OTG interfaces on the Zynq device. A Microchip USB3320
USB 2.0 Transceiver Chip with an 8-bit ULPI interface is used as the PHY. The PHY features a complete HS-USB
Physical Front-End supporting speeds of up to 480Mbs. The PHY is connected to MIO Bank 1/501, which is
powered at 1.8V. The usb0 peripheral is used on the PS, connected through MIO[28-39]. The USB OTG interface
can act as an embedded host or a peripheral device. The USB mode is controlled from software by manipulating
the USB0 peripheral controller in the Zynq. When acting as a peripheral, the USB Micro AB connector (J9) should
be used to connect to a USB host device, and JP1 should not be shorted. When acting as an embedded host, the
USB A connector (J10) should be used to connect to a USB peripheral device, and JP1 should be shorted. The ZYBO
should never have a peripheral device and a host device connected to these two connectors at the same time.
While in host mode, the ZYBO is technically an "embedded host", because it does not provide the required 150 µF
of capacitance on VBUS required to qualify as a general purpose host. It is possible to modify the ZYBO so that it
complies with the general purpose USB host requirements by loading C64 with a 150 µF capacitor and shorting JP2.
Only those experienced at soldering small components on PCBs should attempt this rework. Many USB peripheral
devices will work just fine without loading C64. Whether the ZYBO is configured as an embedded host or a general
purpose host, it can provide 500 mA on the 5V VBUS line.
Note that if your design uses the USB OTG feature in host mode (embedded or general purpose), then the ZYBO
should not be powered via USB (J11), but instead by a battery or wall adapter capable of providing more power.
9
Ethernet PHY
The ZYBO uses a Realtek RTL8211E-VL PHY to implement a 10/100/1000 Ethernet port for network connection. The
PHY connects to MIO Bank 501 (1.8V) and interfaces to the Zynq-7000 AP SoC via RGMII for data and MDIO for
management. The auxiliary interrupt (INTB) and reset (PHYRSTB) signals connect to PL pins to be accessed via
EMIO. The connection diagram can be seen on Fig. 7.
