HardLabs

Zxkbd

jtsiomb·zxkbd·hw/zxkbd.kicad_pcb

Zxkbd PCB layout, top view — open source AVR/Arduino board by jtsiomb
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About the Zxkbd PCB

Zxkbd is an open source AVR/Arduino PCB design by jtsiomb, published on GitHub under the GPL-3.0 license. It is a 2-layer board measuring 148.3 × 48 mm, with 59 components from 22 distinct parts.

Its main chip is the ATmega328P-AU, from the AVR/Arduino family. Other key parts include the 74HC373, 74HC30, pentagon_conn and PS2CONN. By type, the board carries 17 capacitors, 16 ICs, 15 resistors, 6 connectors, 3 switches and 1 transistor.

It belongs with the keyboards and test & measurement designs in this gallery.

From the project

PS/2 keyboard controller for the ZX Spectrum

ZX Spectrum PS/2 keyboard controller ====================================

About ----- This project is an PS/2 keyboard controller for the ZX Spectrum. It makes it possible to connect and use an external PS/2 keyboard with the spectrum. It's based on the a500kbd code: https://github.com/jtsiomb/a500kbd

The PS/2 keyboard controller is built around an AVR atmega168 microcontroller. The firmware reads PS/2 keyboard scancodes, maintains a virtual spectrum keyboard state, and monitors the address bus to keep the data lines going into the ULA continuously up to date with the selected key row state.

Main components on the Zxkbd

74HC37374HC30pentagon_connPS2CONNATmega328P-AU

Zxkbd bill of materials (BOM)

59 components, 22 distinct parts.

QtyPartRefs
8
74HC373
U1, U7, U9, U10, U13, U14, U15, U16
5
74HC30
U2, U3, U4, U5, U6
1
pentagon_conn
U8
1
PS2CONN
U11
1
ATmega328P-AU
U12
1
BC846
Q1
1
14.7456
Y1
1
TAPE
J1
1
LINEOUT
J2
1
AY_IN
J3
1
SCART
J4
1
SERIAL
J5
1
ISP
J6
1
RESET
SW1
1
MAGIC
SW2
1
AVR_RST
SW3
12
0.1uF
C1, C2, C3, C4, C5, C6, C7, C8 +4
3
220uF
C9, C10, C12
2
22pF
C13, C14
5
470R
R1, R2, R3, R4, R9
Show 2 more
QtyPartRefs
4
75R
R5, R6, R7, R8
6
4k7
RN1, RN2, RN3, RN4, RN5, RN6

Zxkbd design files

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

Zxkbd: common questions

What microcontroller does the Zxkbd use?

The Zxkbd is built around the ATmega328P-AU, from the AVR/Arduino family.

How big is the Zxkbd PCB?

The Zxkbd measures 148.3 × 48 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Zxkbd?

59 components, from 22 distinct parts. The full bill of materials is listed on this page.

Where can I download the Zxkbd design files?

From the jtsiomb/zxkbd repository on GitHub, which has the KiCad layout; the links under Design files point to each one.

Can I use the Zxkbd design in my own project?

Yes, under the terms of its GPL-3.0 license, which jtsiomb chose for the repository.

Can I test firmware for the Zxkbd 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.

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