R
Functional Description
+1.2V
+3.3V
SPI
Serial
Flash
VCCINT
P
P
HSWAP
VCCO_0
VCCO_0
I
VCC
DATA_IN
VCCO_2
MOSI
+3.3V
SPI Mode
DIN
DATA_OUT
SELECT
‘0’
‘0’
‘1’
M2
M1
M0
CSO_B
WR_PROTECT
HOLD
W
‘1’
Spartan-3E
CLOCK
Variant Select
FPGA
GND
‘1’
S
VS2
VS1
VS0
+3.3V
‘1’
CCLK
DOUT
INIT_B
+2.5V
JTAG
TDI
+2.5V
VCCAUX
TDO
+2.5V
TDI
TMS
TCK
TDO
TMS
TCK
PROG_B
DONE
GND
PROG_B
Recommend
open-drain
driver
DS312-2_46_082009
Figure 53: SPI Flash PROM Interface for PROMs Supporting READ (0x03) and FAST_READ (0x0B) Commands
S
Although SPI is a standard four-wire interface, various
Figure 53 shows the general connection diagram for those
SPI Flash PROMs that support the 0x03 READ command
or the 0x0B FAST READ commands.
available SPI Flash PROMs use different command proto-
cols. The FPGA’s variant select pins, VS[2:0], define how
the FPGA communicates with the SPI Flash, including
which SPI Flash command the FPGA issues to start the
read operation and the number of dummy bytes inserted
before the FPGA expects to receive valid data from the SPI
Flash. Table 53 shows the available SPI Flash PROMs
expected to operate with Spartan-3E FPGAs. Other com-
patible devices might work but have not been tested for suit-
ability with Spartan-3E FPGAs. All other VS[2:0] values are
reserved for future use. Consult the data sheet for the
desired SPI Flash device to determine its suitability. The
basic timing requirements and waveforms are provided in
Serial Peripheral Interface (SPI) Configuration Timing in
Module 3.
Figure 54 shows the connection diagram for Atmel
DataFlash serial PROMs, which also use an SPI-based pro-
tocol. ‘B’-series DataFlash devices are limited to FPGA
applications operating over the commercial temperature
range. Industrial temperature range applications must use
‘C’- or ‘D’-series DataFlash devices, which have a shorter
DataFlash select setup time, because of the faster FPGA
CCLK frequency at cold temperatures.
Figure 57, page 84 demonstrates how to configure multiple
FPGAs with different configurations, all stored in a single
SPI Flash. The diagram uses standard SPI Flash memories
but the same general technique applies for Atmel
DataFlash.
76
www.xilinx.com
DS312-2 (v3.8) August 26, 2009
Product Specification
XILINX [ XILINX, INC ]
