User manual

Table Of Contents
Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 357
UG585 (v1.11) September 27, 2016
Chapter 12: Quad-SPI Flash Controller
Dual SS, 4-bit Stacked I/O
To reduce the I/O pin count, the controller also supports up to two SPI flash memories in a shared
bus configuration, as shown in Figure 12-7. This configuration increases the maximum addressable
SPI flash memory from 16 MB (24-bit addressing) to 32 MB (25-bit addressing), but the throughput
remains the same as for single memory mode. Note that in this configuration, the device level XIP
mode (read instruction codes of 0xbb and 0xeb), is not supported.
The lower SPI flash memory should always be connected if the linear Quad-SPI memory subsystem
is used, and the upper flash memory is optional. Total address space is 32 MB with a 25-bit address.
In IO mode, the MSB of the address is defined by U_PAGE which is located at bit 28 of register 0xA0.
In Linear address mode, AXI address bit 24 determines the upper or lower memory page. All of the
commands will be executed by the device selected by U_PAGE in I/O mode and address bit 24 in
linear mode.
X-Ref Target - Figure 12-7
Figure 12-7: Quad-SPI Dual SS 4-bit Stacked I/O
UG585_c12_08_102014
Quad-SPI
Controller
Zynq Device
Quad-SPI
Flash
Memory
QSPI0_IO[3:0]
IO[3:0]
CLK
S
QSPI0_SCLK
QSPI0_SS_B
Quad-SPI
Flash
Memory
(Upper)
IO[3:0]
CLK
S
QSPI1_SS_B