Syntax¶

The data must be in one of the following formats: Bin (binary), Hex (hexadecimal), or Address‐Hex (described below).

For hexadecimal values, both upper and lower case can be used. If the data has fewer bits than the specified data width, the most significant bits are filled with 0. Any address not specified will be filled with 0.

Comments can be added at any point after the header (defined below) by starting the comment with a pound sign (#) or two slashes (//). The comment then includes everything to the end of the line. Comments may be added to any of the data, but never add comments to the header.

Header¶

A .mem file starts with a header, which declares the file format, memory size, and address and data display radix for Memory Generator. The syntax of the header is:

#Format=Bin | Hex | AddrHex
#Depth=1 to 65536
#Width=1 to 256
#AddrRadix=index‐number
#DataRadix=index‐number
#Data

Binary: 0
Octal: 1
Decimal: 2
Hexadecimal: 3

For example, the following header says the .mem file is using the binary format for a 32x8 memory. When displayed in Memory Generator, the address will be shown in hexadecimal and the data will be shown in binary.

#Format=Bin
#Depth=32
#Width=8
#AddrRadix=3
#DataRadix=0
#Data

Bin and Hex Formats¶

The data is represented in binary or hexadecimal format. Each line of data specifies the contents for one memory location, starting with address 0. That is, the first line is for address 0, the second line is for address 1, and so on. For each line, the data is interpreted as least significant bit on the right.

For example, in the Bin format, the following lines will initialize address 0 to “00011011”, address 1 to “11111010” (assuming it is a 32x8 memory).

# for a 32x8 memory
11011
11111010

In the Hex format, the following lines will initialize address 0 to “003B”, address 1 to “FB0A” (assuming it is a 32x16 memory).

# for a 32x16 memory
3B
FB0A

AddrHex¶

The data is represented in hexadecimal format. Each line consists of an address followed by a colon and then any number of data words, separated by spaces:

For example:

A0:03 F3 3E 4F
B2:3B 9F

See Also¶

http://help.latticesemi.com/docs/webhelp/eng/wwhelp/wwhimpl/common/html/wwhelp.htm#href=Design%20Entry/memory_initialization_file.htm#1371843&single=true

Size Multiplier¶

The size multiplier depends on the width selected. As files grow larger, their size multipliers will approach those in the table, from above.

Byte Order¶

This format is implicitly big‐endian. Use a -byte‐swap filter if you need something different.