Framethrower (PiStorm) – Ausvantage Wiki

🔥 Framethrower (PiStorm) – Setup Guide

Framethrower is a Denise-socket passthrough board for Amiga OCS/ECS machines (e.g. A500/A2000), designed to route native Amiga video through the PiStorm’s “camera” connector so you can get single-cable HDMI style output with automatic RTG ↔ native switching under Emu68.

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🧰 Hardware you need 🧩 Install steps (Denise socket) ⚙️ Emu68 configuration (cmdline.txt) 🖥️ HDMI 50Hz settings 🔁 Firmware update (UF2) 🧯 Known issues & tips 🔗 Links & downloads

Hardware you need

In addition to the Framethrower board itself, you’ll need the correct FPC ribbon/camera cable.

Required cable

You will need either a Raspberry Pi camera cable or a generic A/B Type 15-pin, 1.0mm pitch FPC (matches the Pi/PiStorm camera connector). Make sure the length suits your case/stack.

Install steps (Denise socket)

Physical installation is simple, but take your time and align pins carefully.

Step 1

Power off the Amiga and unplug everything.

Step 2

Remove Denise from its socket (use a chip puller if possible).

Step 3

Place Framethrower into the Denise socket (check orientation / notch).

Step 4

Place Denise into the Framethrower’s Denise socket.

Step 5

Connect the FPC cable to Framethrower (metallic FPC contacts facing down).

Step 6

Connect the other end of the FPC cable to the Raspberry Pi / PiStorm “camera” connector.

Double-check before power

Make sure Denise is fully seated, Framethrower is fully seated, and the FPC ribbon is straight and locked. Misalignment is the #1 cause of “weird output”.

Emu68 setup (cmdline.txt)

Configure Framethrower via Emu68 boot parameters in cmdline.txt (single line).

Emu68 version note

Emu68 1.0.5 and 1.0.6 already include basic Framethrower support. Newer releases may improve stability and fix early limitations.

Where is cmdline.txt?
Usually in the root of the Emu68 SD card FAT partition. Some images relocate it — check config.txt for a line like cmdline=path/to/cmdline.txt. If it doesn’t exist, create it.

Option A: Integer / pixel-perfect passthrough

Enables integer (pixel perfect) passthrough + automatic RTG/native switching.

unicam.boot unicam.integer

Option B: Smooth scaler (4:3 fullscreen)

Enables scaled 4:3 fullscreen passthrough + automatic RTG/native switching.

unicam.boot unicam.smooth unicam.b=20 unicam.c=0 unicam.phase=60

Important

In cmdline.txt, all parameters must be on one single line, separated by spaces.

HDMI output: set 50Hz (PAL) to reduce tearing

If your Amiga is PAL, setting the Pi’s HDMI output to 50Hz usually feels much better.

Example config.txt: 720p @ 50Hz

disable_overscan=1 # ScreenMode: 720p 50hz hdmi_group=1 hdmi_mode=19

Example config.txt: 1080p @ 50Hz

disable_overscan=1 # ScreenMode: 1080p 50hz hdmi_group=1 hdmi_mode=31

Framethrower firmware update (UF2)

Until an Amiga-side updater exists, firmware updates are done via the onboard USB-C interface.

USB cable requirement

Use a USB-C → USB-A cable. A direct USB-C → USB-C connection typically won’t work for this update mode.

Step 1

Power off the Amiga.

Step 2

Press and hold the button on Framethrower.

Step 3

While still holding the button, power on the Amiga.

Step 4

Release the button and connect USB-C → USB-A from Framethrower to your PC.

Step 5

A USB drive called RP2350 should appear on your PC.

Step 6

Copy (drag & drop) the firmware .UF2 file onto the RP2350 drive.

Step 7

The drive will disappear (dismount) — update complete.

Known limitations & tips (early Emu68 support)

These are common early quirks reported with Framethrower support in older Emu68 builds.

Common issues

• Boot Mode passthrough can be broken with unicam.smooth scaler settings
• NTSC modes may show “garbage” in the lower part of the screen
• unicam.smooth may cause recoverable gurus on Workbench

Practical recommendations

• If you hit glitches, try Option A (unicam.integer) first
• Keep HDMI at 50Hz for PAL setups to reduce tearing
• If you’re using a prebuilt Emu68 image, confirm where cmdline.txt lives (some relocate it)

Links & downloads

Useful references for Emu68 configuration and Framethrower context.

Emu68 Releases Emu68 Options (cmdline) PiStorm32-Lite Hardware (GitHub)