When placed in JTAG boot mode, with the two leftmost pins of JP5 shorted (labeled “JTAG”), 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.
The Eclypse Z7 is 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 the Eclypse Z7 in Independent JTAG mode by shorting unloaded jumper JP3.
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.
The Eclypse Z7 includes two Micron MT41K256M16TW-107 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.
Note:The Eclypse Z7 may alternatively use an ISSI IS43TR16256A(L)-125KBL DDR3L memory. This part is compatible with the
same timings as the Micron part.
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 533 MHz/1066 MT/s are supported.
The Eclypse Z7 was 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.
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, the Eclypse Z7 Vivado board files are available on
theEclypse Z7 Resource 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
certain memory signals.
Board delays are specified for each of the byte groups. These parameters are board-specific and were calculated from the
PCB trace length reports. The DQS to CLK Delay and Board Delay values are calculated specific to the Eclypse Z7
memory interface PCB design.
For more details on memory controller operation, refer to the XilinxZynq Technical Reference manual.
The Eclypse Z7 features a Spansion S25FL128S 4-bit Quad-SPI serial NOR flash. The key device attributes are:
Part number S25FL128S
16MBof memory
1-bit, 2-bit, and 4-bit bus widths supported
General use clock speeds up to 100 MHz, translating to 400 Mbps in Quad-SPI mode
Zynq configuration clock speeds up to 94 MHz
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The Flash memory is used to provide non-volatile code and data storage. It can be used to initialize the PS and PL of the
Zynq device with a Zynq Boot Image (also known as BOOT.BIN) generated using Xilinx tools such as Petalinux or Xilinx
SDK. For information on booting the Eclypse Z7 with a Zynq Boot image, see section “2.2 Quad SPI Boot Mode”.
3. DDR3L Memory
4. Quad-SPI Flash