TI89 <=> PC Keyboard interface
The electronics part is really simple, all the parts can be bought for less than 3 euros altogether.
So as to connect your TI89, I recommend again using a 2.5mm stereo jack socket. The JACK1 terminal is connected with the tip, JACK2 with the middle and JACK3 with the ground.
You can use any keyboard, AT with DIN plug or PS/2 ; only the socket and its pinout will be different.
PS/2 Keyboard :
 Keyboard plug |
 Device socket |
1 - DATA 2 - Leave unconnected 3 - GND 4 - +5V 5 - CLOCK 6 - Leave unconnected |
AT Keyboard :
 Keyboard plug |
 Device socket |
1 - CLOCK 2 - DATA 3 - Leave unconnected 4 - GND 5 - +5V |
Building the device
There is no printed circuit, just fasten the 7805 regulator and the DIN or PS/2 socket to a case, then solder all the other parts directly on their pins.To pick up a keyboard, it's better to try out several ones and measure their current consumption: indeed, it varies a lot from one keyboard to another. According to how much current your keyboard sinks, you may choose to power it from a 9V battery, or from 5 LR6/AA batteries in series.
When the keyboard is correctly powered up, its three LEDs should light up for a short while (just like it happens when you turn on your PC).
The software
This TSR allows you to use the PC keyboard like it's the real TI89 keyboard : there is no need for compliant applications. Run it, then plug the keyboard and turn it on. If the Num Lock indicator lights up, it works :) you can't start typing.This program is en event hook made with h220xTSR, to uninstall it use uninevhk >= 3.00 (provided). Avoid leaving it running when unused, as it increases the battery usage of the calculator.
The version 0.1 still has some issues :
- it doesn't work in assembly programs
- it doesn't either when opening a menu or with some dialog boxes' controls
- trying to transfer a variable over the link port messes all up (If this happens, uninstall the program, it will reset the link port)
> Download