Filter
Top Products
Development System Reference Guide www.xilinx.com 369
Data2MEM Input and Output Files
R
Debugging Information Format DWARF (.drf) files
A Debugging Information Format DWARF (.drf) file is a binary data file that contains the
executable CPU code image, plus debug information required by symbolic source-level
debuggers. These files are produced by the same software compiler tools as .elf files.
Data2MEM reads .drf files wherever .elf files can be used. Because .drf files are binary data,
they are not directly editable. Data2MEM provides some facilities for examining the
content of .drf files.
Memory (.mem) files
A memory (.mem) file is a simple text file that describes contiguous blocks of data. A .mem
file may have as many contiguous data blocks as required. There can be any size gap of
address range between data blocks; however, no two data blocks can overlap an address
range. Because a .mem file is a simple text file, it is directly editable. Data2MEM allows the
free-form use of both slash (//) and asterisk (/*...*/) commenting styles.
The format of .mem files is an industry standard, and consists of two basic elements; hex
address specifier and hex data values. Data2MEM uses .mem files for both data input and
output. See the description of the differences between input and output memory files
below.
Memory (.mem) Files as Output
Output memory files are used primarily for Verilog simulations with third-party memory
models. Therefore, the format follows industry standard use on three key points:
• All data values must be the same number of bits wide, and must be the same width as
expected by the memory model.
• All data values reside within a larger array of values, starting at zero.
• If an address gap exists between two contiguous blocks of data, the data between the
gaps still logically exists but is undefined.
Bit (.bit) files
A bitstream (.bit) file is a binary data file that contains a bit image downloadable to an
FPGA device. Data2MEM replaces the Block RAM data in .bit files, without the
intervention of any Xilinx implementation tools; therefore, Data2MEM both inputs and
outputs .bit files. A .bit file is generated by Xilinx implementation tools. Please refer to
Xilinx implementation tools in this reference manual for details on creating .bit files.
Because .bit files are binary data, they are not directly editable. Data2MEM provides some
facilities for examining the content of .bit files.
Verilog (.v) files
A Verilog (.v) file is a simple text file that Data2MEM outputs, which contains “defparm”
records to initialize Block RAMs. This file is used primarily for pre-synthesis and post-
synthesis simulation. Because a .v file is a simple text file, it is directly editable, but editing
this file is not advised because it is a generated file. Data2MEM allows the free-form use of
both slash (//) and asterisk (/*...*/) commenting styles.