Digilent Genesys ZU Reference Manual page 21

The Genesys ZU features a serial flash memory from ISSI. This memory is used to provide non‐volatile
code and data storage. It can be used to initialize the PS subsystem as well as configure the PL. The key
device attributes are:
Part number: IS25LP256D‐JMLE
Size: 256Mbit / 32Mbyte
1‐bit, 2‐bit and 4‐bit bus widths supported
80MHz Normal Read, Up to 166MHz Fast Read
Up to 664Mb/s in quad‐spi mode
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The Flash is also commonly used to store non‐configuration data needed by the application. If doing this
from a bare‐metal application, the flash memory can be freely accessed using standalone libraries
included with a Xilinx SDK BSP project. If doing this from a Petalinux generated embedded Linux system,
the Flash can be partitioned as desired and mounted/accessed like a standard MTD block device. See the
Petalinux and Xilinx SDK documentation for more information.
The Flash connects to the Quad‐SPI Flash controller of the Zynq UltraScale+ via pins in MIO Bank 0/500
(specifically MIO[0:5]).
The memory is divided into uniform 4 KByte sectors or uniform 32/64 Kbyte blocks. A block consists of
8/16 adjacent sectors.
Two globally unique MAC address are programmed in the last sector, sector 8191.
MAC for Ethernet PHY is stored at address 0x1FFF000
MAC for SFP+ (5EV only) is stored at address 0x1FFF006
The last sector, used to store the MAC addresses, is protected from write and erase. Any attempt to
program or erase the last sector will fail.
The ISSI flash features an Advanced Sector/Block Protection mechanism. Every main flash memory array
block/top sector/bottom sector has a non‐volatile (PPB) protection bit associated with it. When the bit is
0, the sector is protected from program and erase operations.
There is a TBPARM bit that defines the logical location of the parameter block. The parameter block
consists of thirty two 4KB sectors, which replace two 64KB blocks.
When TBPARM is set to 0 the parameter block is in the top of the memory array address space. When
TBPARM is set to 1 the parameter block is at the bottom of the array. TBPARM is OTP(One‐Time
Programmable) and set to 1 when shipped from factory. If TBPARM is programmed to 0, an attempt to