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1541-II-low profile rom switcher

jwestfall69·1541-II-low-profile-rom-switcher·hardware/1541-II-low-profile-rom-switcher.kicad_pcb

1541-II-low profile rom switcher PCB layout, top view — open source AVR/Arduino board by jwestfall69

About the 1541-II-low profile rom switcher PCB

1541-II-low profile rom switcher is an open source AVR/Arduino PCB design by jwestfall69, published on GitHub under the Unlicense license. It is a 2-layer board measuring 18.4 × 41.5 mm, with 5 components from 5 distinct parts.

Its main chip is the ATtiny402-SS, from the AVR/Arduino family. Other key parts include the 27C512. By type, the board carries 2 ICs, 2 connectors and 1 capacitor.

From the project

Thus I decided to make the low profile 1541-II board. Here you can see the difference in height between them.

Thus I decided to make the low profile 1541-II board. Here you can see the difference in height between them.

In order for the low profile board to work we need to take control of A14 (PIN 27) and A15 (PIN 1) on the 27c512 ROM. These are normally tied to VCC on the 1541-II board. To do this we cut these legs from the socket used on the low profile board to prevent them connecting to the 1541-II board. This allows the ATtiny402 MCU to control those address lines on the 27c512 eprom for switching between kernels.

1541-II-low profile rom switcher, from the project README
From the project README

Main components on the 1541-II-low profile rom switcher

27C512ATtiny402-SS

1541-II-low profile rom switcher bill of materials (BOM)

5 components, 5 distinct parts.

QtyPartRefs
1
27C512
U1
1
ATtiny402-SS
U2
1
UPDI Header
J1
1
UART
J2
1
100nf
C1

1541-II-low profile rom switcher design files

The KiCad project lives in the jwestfall69/1541-II-low-profile-rom-switcher repository on GitHub; these links point at the commit this page was built from.

1541-II-low profile rom switcher: common questions

What microcontroller does the 1541-II-low profile rom switcher use?

The 1541-II-low profile rom switcher is built around the ATtiny402-SS, from the AVR/Arduino family.

How big is the 1541-II-low profile rom switcher PCB?

The 1541-II-low profile rom switcher measures 18.4 × 41.5 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the 1541-II-low profile rom switcher?

5 components, from 5 distinct parts. The full bill of materials is listed on this page.

Where can I download the 1541-II-low profile rom switcher design files?

From the jwestfall69/1541-II-low-profile-rom-switcher repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.

Can I use the 1541-II-low profile rom switcher design in my own project?

Yes, under the terms of its Unlicense license, which jwestfall69 chose for the repository.

Can I test firmware for the 1541-II-low profile rom switcher 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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