Monitor Firmware Version 1.10

About the new monitor

Routines were added to provide output to a parallel printer, together with several extra commands. The printer cable is the type used by the BBC Micro and plugs into CON2. A few additional components are required to enable the port; see the printer-port modification for details.

To use the printer from your own programs, write to zero-page location OPREG ($5F):

• setting bit 0 enables the LCD;
• setting bit 1 enables the printer;
• setting both bits sends output to both devices.

The monitor source refers to a serial printer. The hardware for that interface was never completed, so it does not work.

The source, Intel HEX file and assembler listing are available from the software downloads page.

Additional monitor commands

Hex Dump — Shift-9

Prints the memory between two supplied addresses in hexadecimal.

Disassemble — Shift-8

Disassembles the code between two supplied addresses.

Offset — Shift-7

Calculates the offset byte used by branch instructions such as BNE.

Transfer Memory — Shift-6

Copies a block of memory from one location to another.