TranzMON

TranzMON is a resident monitor for the Tranz 330 POS terminals. It turns the POS into a multi purpose Z80 based computer that can also be used as an educational tool.

It's sufficient to burn the binary into a 27C256 EPROM and put it in place of the original one at U6 on the control board.

Supported functions

• Serial console at 19200bps 8-n-1

• External keypad/VFD input

• Port IN/OUT (keypad and console)

• Memory READ/WRITE (keypad and console)

• Jump execution to an address (keypad and console)

• Memory upload/download via XMODEM (console)

• RTC (console and keypad)

Console commands

• O xx yy -> Output value yy to port xx
• I xx -> Input from port xx
• J xxxx -> Jump execution @xxxx
• F xxxx yy zz -> Fill zz bytes of RAM with yy starting @xxxx
• W xxxx yy -> Write zz @xxxx
• R xxxx yy -> Print yy 16b blocks of RAM starting @xxxx
• X xxxx -> Download data via XMODEM @xxxx
• U xxxx yyyy -> Upload yyyy bytes via XMODEM from xxxx
• T ddMMyyhhmmssD -> Show or set current date (D is day of week, starts at 0 with Sunday)

Keypad commands

• 1: Memory inspection/edit mode
• 2: Port input mode
• 3: Port output mode
• 4: Jump mode
• 5: RTC set mode

Function table

Starting at a fixed address of 0x7F00, the monitor provides an address table of common functions that reside in ROM code, and that can be called from code uploaded in RAM.

TODO: Describe the table