TheZyboZ7supports booting from a microSD card inserted into connector J4. The following procedure will allow you to
boot the Zynq from microSD with a standard Zynq Boot Image created with the Xilinx tools:
1. Format the microSD card with a FAT32 file system.
2. Copy the Zynq Boot Image created with Xilinx SDK to the microSD card.
3. Rename the Zynq Boot Image on the microSD card to BOOT.bin.
4. Eject the microSD card from your computer and insert it into connector J4 on theZyboZ7.
5. Attach a power source to theZyboZ7and select it using JP6.
6. Place a single jumper on JP5, shorting the two leftmost pins (labeled “SD”).
7. Turn the board on. The board will now boot the image on the microSD card.
TheZyboZ7has an onboard 16MB Quad-SPI Flash that the Zynq can boot from. Documentation available from Xilinx
describes how to use Xilinx SDK to program a Zynq Boot Image into a Flash device attached to the Zynq. Once the Quad
SPI Flash has been loaded with a Zynq Boot Image, the following steps can be followed to boot from it:
1. Attach a power source to theZyboZ7and select it using JP6.
2. Place a single jumper on JP5, shorting the two center pins (labeled “QSPI”).
3. Turn the board on. The board will now boot the image stored in the Quad SPI flash.
When placed in JTAG boot mode, the processor will wait until software is loaded by a host computer using the Xilinx
tools. After software has been loaded, it is possible to either let the software begin executing, or step through it line by line
using Xilinx SDK.
It is also possible to directly configure the PL over JTAG, independent of the processor. This can be done using the Vivado
Hardware Server.
TheZyboZ7is configured to boot in Cascaded JTAG mode, which allows the PS to be accessed via the same JTAG port
as the PL. It is also possible to boot theZyboZ7in Independent JTAG mode by loading a jumper in JP3 and shorting it.
This will cause the PS to not be accessible from the onboard JTAG circuitry, and only the PL will be visible in the scan
chain. To access the PS over JTAG while in independent JTAG mode, users will have to route the signals for the PJTAG
peripheral over EMIO, and use an external device to communicate with it.
TheZyboZ7includes two Micron MT41K256M16HA-125 DDR3L memory components creating a single rank, 32-bit
wide interface and a total of 1 GiB (Gibi-byte, or 1,073,741,824 bytes) of capacity. The DDR3L is connected to the hard
memory controller in the Processor Subsystem (PS), as outlined in the Zynq documentation.
The PS incorporates an AXI memory port interface, a DDR controller, the associated PHY, and a dedicated I/O bank.
DDR3L memory interface speeds up to 533MHz/1066 Mbps are supported.
ZyboZ7was routed with 40 ohm (+/-10%) trace impedance for single-ended signals, and differential clock and strobes set
to 80 ohms (+/-10%). A feature called DCI (Digitally Controlled Impedance) is used to match the drive strength and
termination impedance of the PS pins to the trace impedance. On the memory side, each chip calibrates its on-die
termination and drive strength using a 240 ohm resistor on the ZQ pin.
Due to layout reasons, the two lower data byte groups (DQ[0-7], DQ[8-15]) were swapped. To the same effect, the data bits
inside byte groups were swapped as well. These changes are transparent to the user. During the whole design process the
Xilinx PCB guidelines were followed.
Both the memory chips and the PS DDR bank are powered from the 1.35V supply. The mid-point reference of 0.675V is
created with a simple resistor divider and is available to the Zynq as external reference.
For proper operation it is essential that the PS memory controller is configured properly. Settings range from the actual
memory flavor to the board trace delays. For your convenience, theZyboZ7Vivado board files are available on
theZyboZ7Resource Centerand automatically configure the Zynq Processing System IP core with the correct
parameters.
For best DDR3L performance, DRAM training is enabled for write leveling, read gate, and read data eye options in the PS
Configuration Tool in Xilinx tools. Training is done dynamically by the controller to account for board delays, process
variations and thermal drift. Optimum starting values for the training process are the board delays (propagation delays) for
2.2 Quad SPI Boot Mode
2.3 JTAG Boot Mode
3 DDR3L Memory