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Dongles
From v1.2 onward the PICO9918 does not carry a video connector at all. It exposes its video output over a 12-pin FFC interface, and a small dongle on the other end of the cable decides what comes out: VGA, HDMI or SCART RGB. One cable, three choices, swappable without touching the board.
| Dongle | Output | Signal | Audio | Powered |
|---|---|---|---|---|
| VGA Dongle | DE-15 VGA | 640x480 @ 60 Hz progressive | No | No |
| Digital AV Dongle | HDMI | 640x480 @ 60 Hz progressive | Yes, from a separate lead | Yes, from FFC pin 12 |
| SCART AV Dongle | SCART RGBs, via a 10-pin Sega Saturn Mini-DIN | PAL 576i @ 50 Hz, or NTSC 480i @ 60 Hz | Yes, from a separate lead | Yes, from FFC pin 12, passed out to the cable |
All three fit any FFC-equipped board: PRO v2.0, v1.3 and v1.2.
The firmware picks its output driver at boot. Only the SCART dongle needs detecting, and it is detected automatically, with nothing to set. VGA and HDMI both run from the same VGA driver and need nothing configured. Display Output covers how that decision is made and how to change it without ending up on a display that cannot show you the configurator.
Note
The detect probe runs once, at boot, before video starts. Swapping dongles on a powered board will not change the output, so power the host off first.
Cables are 12-pin, 0.5 mm pitch, and any dongle takes the same one, so a spare is a spare. PICO9918 FFC cables come in 120 mm, 200 mm and 300 mm lengths.
| Pin | Signal | Notes |
|---|---|---|
| 1 | BOOT | Optional, and unconnected on most dongles. See below |
| 3 | RED | |
| 5 | GREEN | |
| 7 | BLUE | |
| 9 | HSYNC | Also used to detect the SCART dongle |
| 11 | VSYNC | |
| 12 | +5V | Powers the Digital AV Dongle's encoder. The SCART AV Dongle passes it out on Mini-DIN pin 4, which the cable needs to switch the display to its AV input and to RGB. Only the VGA Dongle leaves it unconnected |
| 2, 4, 6, 8, 10 | GND | Ground return, one immediately ahead of every signal |
Pin 1 is the triangle end. The board silkscreens a small triangle beside the socket, and that is what the numbering above is keyed to.
Pin 1 carries BOOT, not ground. On the PRO v2.0 board it is brought out by closing an unmarked solder jumper beside the FFC socket; there is no silkscreen label on it, so the figure above rings it. Most dongles leave pin 1 unconnected, but newer ones fit pads for a BOOT button, and that is worth having: with a USB-C extension run out of the case, it puts the board into bootloader mode for a firmware update without opening the machine.
Two things follow from that layout and are worth knowing before you wire anything to it:
- Every signal has a ground ahead of it. Pins 2, 4, 6, 8 and 10 are grounds, one immediately before each of the five video signals on the odd pins 3 to 11. On a flat cable that interleave is what keeps the sync edges clean.
- Audio is not on the interface. Both the HDMI and the SCART dongles take audio from a separate two-pin lead soldered to the host mainboard, not from the PICO9918. Their own pages have the wiring.
For fitting the cable, including which way up the contacts go, see Hardware Setup. Inserted the other way up a dongle simply does not work.
The PRO v2.0 board did not change the pinout, but it changed two things about the interface:
- Additional power filtering, specifically to improve power delivery to the HDMI dongle.
- An optional BOOT pin on FFC pin 1, enabled by closing the unmarked solder jumper beside the socket.
The FFC interface arrived with v1.2 (2024-11-26), along with the separate VGA dongle PCB. Earlier boards had their video connector on the board itself, so none of the dongles above fit them:
| Board | Video connector |
|---|---|
| PRO v2.0, v1.3, v1.2 | 12-pin 0.5 mm FFC, dongle on the far end |
| v1.1, v1.0, v0.4 | 6-pin 1.25 mm JST header, on the board |
| v0.3 | Its own separate VGA breakout board |
The JST header arrived with v0.4 (2024-07-16), the first fully integrated single-board revision, and it carries the same five video signals plus ground in six pins.
| Pin | Signal | Notes |
|---|---|---|
| 1 | VSYNC | 47 Ω in series (R23) |
| 2 | HSYNC | 47 Ω in series (R22) |
| 3 | BLUE | |
| 4 | GREEN | |
| 5 | RED | |
| 6 | GND |
The board prints the order as a ground symbol followed by R G B H V, which is the same sequence read from pin 6 back to pin 1.
Two things make this a different proposition from the FFC interface:
- No ground interleave and no power pin. Six pins carry five signals and one ground, so there is nothing spare.
- One accessory, permanently attached. These boards only ever had a VGA dongle, and its cable was hard-wired into it. There was no detachable cable to swap, and no HDMI or SCART option.
Note
The two interfaces are not interchangeable, and the pin counts alone make that clear. An FFC dongle needs an FFC-equipped board, so HDMI or SCART out of a v1.1 or earlier board means changing the board.
- VGA Dongle - the default output, and a passive one
- Digital AV Dongle - HDMI, with audio and a 5V rail
- SCART AV Dongle - SCART RGBs, and the dongle that gets detected
- F18A to PICO9918 Dongle Adapter - drives these dongles from an F18A MkI instead
- TI-99/4A No-Cut Mod - routes a dongle out of a TI-99/4A without cutting the case
- Hardware Setup - fitting the cable, and which way up
- Display Output - how the driver is chosen, and changing it safely
- Hardware - board revisions and what each one changed
- Schematics - component-level schematics