HardLabs

Keyboard

danwerner21·TI99_22·Keyboard/Keyboard.kicad_pcb

Keyboard PCB layout, top view — open source AVR/Arduino board by danwerner21
Simulate this board

About the Keyboard PCB

Keyboard is an open source AVR/Arduino PCB design by danwerner21, published on GitHub. It is a 2-layer board measuring 282.7 × 108.3 mm, with 57 components from 56 distinct parts.

Its main chip is the ATtiny13A-P, from the AVR/Arduino family. Other key parts include the 74LS125. By type, the board carries 48 switches, 3 resistors, 2 ICs, 2 diodes, 1 connector and 1 capacitor.

It belongs with the keyboards and audio designs in this gallery.

From the project

a 2022 replica of the classic TI/994a, using obtainable parts

Note that this is not a fully tested project at this point. . . .

This is based Rob Krenicki's design that is based on the HackMac KiCAD schematics. I have made several changes to the original design including:

Placing 32K of 16bit wide fast ram on the board to fully populate the address space Placing an EPROM on the main board that can be used as an on-board cartridge ROM adding a header to allow a microcontroller to replace the GROM chips (hopefully this can be moved on-board soon) replacing the video DRAM with SRAM Updating the Keyboard header to support a soft caps lock switch on the…

Keyboard, from the project README
From the project README

Main components on the Keyboard

ATtiny13A-P74LS125

Keyboard bill of materials (BOM)

57 components, 56 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
ATtiny13A-P
U1
1
74LS125
U2
1
Computer
J1
1
SLASH
SW1
1
PERIOD
SW2
1
COMMA
SW3
1
M
SW4
1
N
SW5
1
EQUALS
SW6
1
COLON
SW7
1
L
SW8
1
K
SW9
1
J
SW10
1
H
SW11
1
SPACE
SW12
1
P
SW13
1
O
SW14
1
I
SW15
1
U
SW16
1
Y
SW17
Show 36 more
QtyPartRefs
1
ENTER
SW18
1
0
SW19
1
9
SW20
1
8
SW21
1
7
SW22
1
6
SW23
1
Z
SW24
1
X
SW25
1
C
SW26
1
V
SW27
1
B
SW28
1
LOCK
SW29
1
A
SW30
1
S
SW31
1
D
SW32
1
F
SW33
1
G
SW34
1
SHIFT
SW35
1
SHIFT
SW36
1
Q
SW37
1
W
SW38
1
E
SW39
1
R
SW40
1
T
SW41
1
CTRL
SW42
1
1
SW43
1
2
SW44
1
3
SW45
1
4
SW46
1
5
SW47
1
FNCT
SW48
1
Alpha
D1
1
Power
D2
1
0.1µF
C1
2
470Ω
R1, R2
1
1KΩ
R3

Keyboard design files

The KiCad project lives in the danwerner21/TI99_22 repository on GitHub; these links point at the commit this page was built from.

Keyboard: common questions

What microcontroller does the Keyboard use?

The Keyboard is built around the ATtiny13A-P, from the AVR/Arduino family.

How big is the Keyboard PCB?

The Keyboard measures 282.7 × 108.3 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Keyboard?

57 components, from 56 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.

Where can I download the Keyboard design files?

From the danwerner21/TI99_22 repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.

Can I use the Keyboard design in my own project?

The repository has no license, so all rights stay with danwerner21. Use it as a reference, and ask the author before reusing the design.

Can I test firmware for the Keyboard without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug AVR/Arduino firmware against it before you order a PCB.

More boards in TI99_22

Similar boards