This format is also known as the Ascii\[hy]Space\[hy]Hex or Ascii\[hy]Hex\[hy]Space format. If you know who invented this format, please let me know. If you have a better or more complete description, I'd like to know that, too.

The file starts with a start\[hy]of\[hy]text (STX or Control\[hy]B) character (0x02). Everything before the STX is ignored.

Each data byte is represented as 2 hexadecimal characters, followed by an "execution character". The default execution character is a space, although many programs which write this format omit the space character immediately preceding end\[hy]of\[hy]line.

The address for data bytes is set by using a sequence of W$AnnnnW, characters, where nnnn is the 4\[hy]character ascii representation of the address. The comma is required. There is no need for an address record unless there are gaps. Implicitly, the file starts a address 0 if no address is set before the first data byte.

The file ends with an end\[hy]of\[hy]text (ETX or Control\[hy]C) character (0x03). Everything following the ETX is ignored.

It is also possible to specify a running 16\[hy]bit checksum using a sequence of W$SnnnnW, characters, although this usually appears after the ETX character and is thus often ignored.

Variant Forms

In addition to a space character, the execution character can also be percent (%) called "ascii\[hy]hex\[hy]percent" format, apostrophe (') or comma (,) called "ascii\[hy]hex\[hy]comma" format. The file must use the same execution character throughout.

If the execution character is a comma, the address and checksum commands are terminated by a dot (.) rather than a comma (,).

Size Multiplier

In general, binary data will expand in sized by approximately 3.0 times when represented with this format.


Here is an example ascii\[hy]hex file. It contains the data \[lq]Hello, World[rq] to be loaded at address 0x1000.

^B $A1000,
48 65 6C 6C 6F 2C 20 57 6F 72 6C 64 0A ^C


\*(n) version \*(v)

Copyright \*(Y) Peter Miller

The \*(n) program comes with ABSOLUTELY NO WARRANTY; for details use the '\*(n) -VERSion License' command. This is free software and you are welcome to redistribute it under certain conditions; for details use the '\*(n) -VERSion License' command.


Peter Miller E\[hy]Mail: [email protected]
/\ /\ *