Tom's Life Bits

The VeriFone Tranz 330 is one of those ubiquitous credit card readers you see all over the place.

Looks like it's a Z80 based board. Inside, it's all 5V, but it has a voltage regulator so you can plug a 7.5V-9V AC Adapter into it.

Inside, it's two pieces. There's the bottom board (the motherboard), that has all the intelligence, and a top board with all the peripherals on it, like an alphanumeric display, a keypad, a piezo speaker, and the mag stripe reader.

Conveniently, the top board and bottom board are connected through a .1“ spaced header. This makes it easy to hack.

I suppose I could flash some Z80 machine code onto that EPROM? But really, why bother? I can replace this board completely with some AVR chips _and_ have room left over for a bunch of batteries.

The upper board seems to be just peripherals for the bottom board, all conveniently accessible through a 1×20-pin female header block.

There's a VFD Display with controller chip, a 4×4 button pad, a speaker, and a mag stripe reader. I expect to be able to control all of these through the header block.

The Controller Chip seems to be a simple serial shift-register controlled thing.

I expect the button pad will be a simple 4 row, 4 column matrix. I expect 8 of the pins on the header will be for the button pad.

I expect one of the pins will be to the piezo buzzer.

Probably one pin for the mag stripe reader too?

That leaves 5 pins unaccounted for.

Pin  1 - Row 1 of the keypad
Pin  2 - Row 2 of the keypad
Pin  3 - Row 3 of the keypad
Pin  4 - Row 4 of the keypad
Pin  5 - Column 4 of the keypad
Pin  6 - Column 3 of the keypad
Pin  7 - Column 2 of the keypad
Pin  8 - Column 1 of the keypad
Pin 13 - /POR on the OKI display chip.  Set this low for 
         200ns to reset the chip.
Pin 14 - DATA on the OKI display chip.
Pin 15 - SCLK on the OKI display chip.
Pin 16 - +5V for the board.
Pin 18 - Speaker
Pin 20 - GND for the board.