Platform Cable USB II
DS593 (v1.2.1) March 17, 2011
18
Indirect SPI
When used with Xilinx design tools, Platform Cable USB II can be used to indirectly program some third-party SPI serial
flash PROMs via the target FPGA's JTAG port. For a complete description on using Platform Cable USB II for indirect
programming of third-party SPI serial flash PROMs and for a complete list of supported SPI serial flash memories, refer to
Indirect Programming of SPI Serial Flash PROMs with Spartan-3A FPGAs
.
Indirect BPI
When used with Xilinx design tools, Platform Cable USB II can be used to indirectly program Platform Flash XL, or some
third-party NOR flash memories (BPI PROMs) via the target FPGA's JTAG port. For a description of the indirect Platform
Flash programming solution, see
Platform Flash XL User Guide
.
X-Ref Target - Figure 18
Notes:
1.
The pin names for a ST Microsystems M25Pxx serial flash device are shown in this example. SPI flash devices from other vendors can have
different pin names and requirements. Refer to the SPI flash data sheet for the equivalent pins and device requirements.
2.
The example shows the interconnect and device requirements for a Xilinx Spartan-3E FPGA. Other SPI-capable FPGAs can have different
pin names and requirements. Please refer to the FPGA data sheet for equivalent pins and device requirements.
3.
The cable uses an open-drain driver to control the pseudo ground (PGND) signal — an external pull-up resistor is required.
4.
Attach the following 2-mm connector pins to digital ground: 3, 5, 7, 9 and 11.
5.
Typically, an FPGA and other slave SPI devices (not shown) are connected to the SPI bus. The other devices on the SPI bus must be disabled
when the cable is connected to the 2-mm connector to avoid signal contention. When a Xilinx FPGA is connected to the SPI bus, the cable
holds the FPGA PROG_B pin Low to insure the FPGA SPI pins are 3-stated.
Figure 18:
Example of Direct SPI Topology
MOSI
PROG_B
GND
Spartan-3E
(2)
FPGA
VCCINT
VCCO_0
VCCO_2
VCCA
UX
VCC
W
HOLD
D
DIN
Q
CSO_B
S
CCLK
C
GND
ST Micro
M25Pxx
(1)
SPI Flash
2
8
10
4
6
13
*
V
REF
MISO
MOSI
SS
SCK
PGND
GND
(4)
2 mm
Connector
+ 3.3V
SPI Bus
(5)
+2.5V
+3.3V
+1.2V
+3.3V
4.7 k
Ω
(3)
+ 2.5V
‘1’
‘1’
DS593_18_021508
