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15-25
LatticeECP2/M sysCONFIG Usage Guide
Mode Specific
SPI/SPIm
• Q. How do I program the SPI Serial Flash once it’s on the board?
A.
Connect the SPI Serial Flash to the LatticeECP2/M as shown in this document, then use ispVM, and a Lattice
ispDOWNLOAD cable connected to the JTAG port, to program the bitstream into the Flash.
LatticeECP2/M devices have a JTAG instruction for programming the SPI Serial Flash. This JTAG instruction
connects the JTAG TCK internally to the CCLK which drives the SPI clock during programming. After launching
ispVM, click on the
Scan
button to scan the devices in the JTAG chain, select the LatticeECP2/M device, then
click
Edit>Edit Device
to launch the Device Information window. In the Device Information window, select
SPI
Flash Programming
for the Device Access Options to open the SPI Serial Flash Device window. Select the SPI
Serial Flash device and the bitstream data file for programming the SPI Serial Flash.
• Q. Are there any special requirements for wiring the SPI Flash to the LatticeECP2/M?
A.
Other than connecting the Flash to the right pins the only other suggestion is to add a 4.7K pull-down resistor
between CCLK and ground. This keeps CCLK quite during V
CC
ramp-up.
• Q. Can I use 2.5V to power the SPI Flash?
A.
Today all SPI Serial Flash of the “25” type are 3.3V, so the Flash, and V
CCIO8
, must be connected to 3.3V.
• Q. Can I use something other than a “25” type SPI Serial Flash?
A.
Only devices that recognize a read op-code of 03h may be used with the LatticeECP2/M. Please refer to
Table 15-6 for a list of vendors.
• Q. My design is small, can I use a smaller-than-recommended SPI Flash?
A.
The state of all of the device fuses is contained in the bitstream, whether they are part of the design or not.
The size of the design does not affect the size of the bitstream.
Serial
• Q. Can I use a free running clock for Slave Serial mode?
A.
The LatticeECP2/M clocks data in on every rising edge of CCLK so there should only be one rising clock edge
for each data bit.
• Q. Is the bitstream for the serial modes different from the bitstream for other modes?
A.
All sysCONFIG bitstreams are the same, they can be different file types, such as hex or binary, but the data is
the same.
Parallel
• Q. My processor is generating all of the proper control signals but the LatticeECP2/M won’t configure,
and INITN goes high and stays high while DONE stays low. What’s wrong?
A.
D0 is the MSB and D7 is the LSB. Try reversing the bit order for each byte in the bitstream. You can do this
using your processor or you can generate a bit mirrored file using ispVM. Lattice recommends using your proces-
sor so that you don’t have to remember to bit mirror the file.
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