Vetus Pars Retro Chip Tester – User Guide

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1. Introduction

The Vetus Pars Retro Chip Tester is a standalone, microcontroller-driven diagnostic tool designed for testing vintage ICs such as:
• DRAM (4164, 41256, etc.)
• SRAM
• 7400-series logic ICs
• CPUs and misc. chips
• Other TTL/CMOS devices

It uses a 40-pin ZIF socket, a full-color ST7735 display, and a 3-button navigation system to make chip selection and testing simple and intuitive.

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2. Hardware Overview

Your Vetus Pars board contains the following components:
• 40-pin ZIF Socket — Insert ICs here for testing.
• 3 Navigation Buttons
• Button 1 – Back
• Button 2 – OK / Select
• Button 3 – Down / Scroll
• Reset Button — Resets the MCU
• BOOT0 Button — Hold this and power-cycle the device to enter DFU mode for firmware flashing.
• Output Header (Auxiliary 3.3V + GND) — Intended for accessories switching with MOSFET.
(Referred to as “fan control” in firmware.)
• USB-C Connector — Used only for:
• Firmware updates via DFU mode
• Uploading chip tests, fonts, and images via Vetus software

DO NOT use anything other than USB-C or 5v power supply.

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3. Power Requirements

This is extremely important:

✔ You MUST use a 5V power supply.
• 5.0V regulated
• 500mA recommended
• 100mA may work for many chips, but older chips often require more current.

-3.3V will NOT power the device.

-6v+ could damage the Vetus Pars
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4. Buttons and Navigation

The Vetus Pars uses a simple three-button interface:

Button 1 – Back

Moves up one menu or cancels a selection.

Button 2 – OK (Select)

Accepts the highlighted item or begins a chip test.

Button 3 – Down

Moves the highlight down through menu options.

These three buttons are used throughout the entire UI — no other controls are needed for daily operation.

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5. Booting Into DFU Mode (Firmware Update)

The Vetus Pars uses an STM32H7 microcontroller. To update firmware:
1. Power OFF the unit.
2. Press and hold the BOOT0 button.
3. While holding BOOT0, power the device ON.
4. Release BOOT0.
5. The device is now in DFU Mode, ready for flashing via dfu-util or STM32CubeProgrammer.

Reset alone cannot enable DFU mode.
It must be BOOT0 + power cycle.

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6. Basic Operation

Step 1 – Insert your chip

Open the ZIF socket, place the chip at the top of the socket, pin-1 aligned, and close the lever firmly.

Step 2 – Power the device

Use a regulated 5V power supply.

Step 3 – Browse the main menu

Use:
• Down = scroll
• OK = select
• Back = return

Step 4 – Search by Type

Choose the chip family:
• DRAM
• SRAM
• CPU
• 7400 Series
• I/O
• Other

Step 5 – Select the first letter

A graphical letter grid appears.
Choose the starting letter of the chip you want to test.

Step 6 – Select from the matching chips

A scrollable list of chips appears.
Choose your exact chip type and press OK.

Step 7 – Test results

The Vetus Pars will run a complete diagnostic tailored to your chip.
Results show:
• Pass / Fail
• Error details
• Any optional test messages
• Optional screen updates depending on the chip test routine

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7. Auxiliary Power Header (Fan / 3.3V Output)

The board includes a small 3.3V/GND header intended for:
• Cooling fans
• Light modules
• Small accessories

This output is limited and not meant for powering external circuits.
Refer to firmware for fan-control behavior.

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8. Upload Mode (Using USB-C)

Upload Mode allows transfer of:
• New chip definitions
• Fonts
• Images
• Firmware test programs

You can enter upload-mode by clicking ok on USB at the bottom of the main menu. You cannot upload tests or test files unless you are in upload-mode.

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9. Safety Notes
• Always use a proper 5V power supply.
• Insert chips carefully to avoid bent pins.
• Never insert or remove a chip while the unit is powered.
• High-current vintage ICs may get warm (not HOT) — this is normal.
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10. Troubleshooting

Device doesn’t power on
• Ensure your 5V supply is actually supplying 5V.
• Check that the switch functions properly.

Chip tests instantly fail
• Ensure pin-1 alignment is correct.
• Make sure the pins are seated properly.
• Depending on the test it could simply be a bad chip. Some tests can end immediately on fault.

Cannot enter DFU mode
• You must:
1. Power off
2. Hold BOOT0
3. Power on
4. Make sure the USB is connected to the computer.

Menu doesn’t respond
• Check your navigation buttons.
• Reset the unit if necessary.