************** Homebrew Keypad for Playstation Portable V1 *********************

Art 2006.

Hi Guys,
This is part of a larger project that I completed years ago that required a numeric
kepad to input user data to another microcontroller circuit.

I have modified the Keypad part of the circuit for use with Playstation Portable Homebrew.
Developers may find a use for a numeric keypad, and perhaps later on, full alphanumeric
support with more keys :) This could have been done many months ago.

For now, I thought a compact keypad was the neatest solution that your average user could
produce at home. I have used the pictured matrix keypad in many projects, and it can be
neatly housed in black enclosures. Electronics knowledge and soldering ability is required
to complete this project. A pic programmer is required also, to write the firmware to the
pic microcontroller in the circuit.
Since the remote serial connector is required, the PSP headphone remote may need to be
destroyed to complete this project. I have a few now, so it didn't bother me to sacrifice a couple.

I am open to suggestions on how to produce a NEAT keypad with around 55 keys.
So far, the reason I haven't done it, as discussed on the forums is neatness of the finished project.

The microcontroller driver supports a shift key to give some keys second functions that
are indicated on the schematic keypad.
A developer (C or LUA), could map these keys any way he/she (probably he) wanted,
since the keypad just outputs key codes that represent the key being pressed.
Shift has to be held down to output the keys second function code.

All data is output at 2400 baud which is supported by LUAplayer and therefore, must also
be supported by PSPSDK since LUAplayer is written in C.

ps. The orange and purple dots on the schematic are supposed to be joined to the corresponding orange
and purple dots on the crystal part of the circuit. I ran out of room to draw it in the correct location.
pps. The words 'Enter' and 'Exit' on the keypad drawing only suggest that's what the buttons be used for.

*********************************************************************************

Hex Key Codes output by the completed circuit are as follows:

Key Press : output code

1 : 01
2 : 02
3 : 03
4 : 04
5 : 05
6 : 06
7 : 07
8 : 08
9 : 09
0 : 00
* : FF
# : FE
A : 0A (user pressed shift + 1)
B : 0B (user pressed shift + 2)
C : 0C (user pressed shift + 3)
D : 0D (user pressed shift + 4)
E : 0E (user pressed shift + 5)
F : 0F (user pressed shift + 6)

0 : AA (user held down the 0 key as unit was powered up)

There are other special functions that are implemented, but not mentioned here.
Give me a yell on PSP Updates forums for more info if required.

Cheers, Art.

***********************************************************************************

END OF FILE.
