User guide

Spartan-6 FPGA Configuration User Guide www.xilinx.com 75
UG380 (v2.7) October 29, 2014
Configuration Data File Formats
Configuration Data File Formats
Xilinx design tools can generate configuration data files in a number of different formats,
as described in Table 5-4. BitGen converts the post-PAR NCD file into a configuration file or
a bitstream. PROMGen, the PROM file generator, converts one or more bitstream files into
a PROM file. PROM files can be generated in a number of different file formats and does
not need to be used with a PROM. They can be stored anywhere and delivered by any
means.
Bitstream Overview
The Spartan-6 FPGA bitstream contains commands to the FPGA configuration logic as
well as configuration data. Table 5-5 gives a typical default bitstream length for each of the
Spartan-6 devices. Compression can provide a smaller bitstream.
Table 5-4: Configuration File Formats
File
Extension
Bit Swapping
(1)
Xilinx Software
Tool
(2)
Description
BIT
Not
Bit Swapped
BitGen (generated by
default)
Binary configuration data file containing header information
that does not need to be downloaded to the FPGA. Used to
program devices from iMPACT software with a programming
cable.
RBT
Not
Bit Swapped
BitGen (generated if
-b option is set)
ASCII equivalent of the BIT file containing a text header and
ASCII 1s and 0s. (Eight bits per configuration bit.)
BIN
Not
Bit Swapped
BitGen (generated if
-g Binary:yes
option is set) or
PROMGen
Binary configuration data file with no header information.
Similar to BIT file. Can be used for custom configuration
solutions (for example, microprocessors), or in some cases to
program third-party PROMs.
MCS
EXO
Bit Swapped
PROMGen or
iMPACT software
ASCII PROM file formats containing address and checksum
information in addition to configuration data. Used mainly for
device programmers and iMPACT software.
HEX
Determined
by User
PROMGen or
iMPACT software
ASCII PROM file format containing only configuration data.
Used mainly in custom configuration solutions.
CFI N/A
PROMGen or
iMPACT software
Data file used by iMPACT software to determine PROM
options to set such as x2 and x4 data width or version control.
Notes:
1. Bit swapping is discussed in the Bit Swapping section.
2. For complete BitGen and PROMGen syntax, refer to UG628
, Command Line Tools User Guide.
Table 5-5: Spartan-6 FPGA Bitstream Length
Device Total Number of Configuration Bits
(1)
6SLX4 2,731,488
6SLX9 2,742,528
6SLX16 3,731,264
6SLX25 6,440,432
6SLX25T 6,440,432