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VGA Dongle
The VGA dongle is the PICO9918's default video output. It is a passive adapter that breaks the board's 12-pin FFC video interface out to a standard DE-15 VGA connector, so any VGA monitor, capture device or upscaler can be driven directly. Nothing needs configuring: with the VGA dongle fitted the firmware boots straight into VGA mode.
The VGA dongle is compatible with all FFC-equipped PICO9918 boards:
- PICO9918 PRO v2.0
- PICO9918 v1.3
- PICO9918 v1.2
v1.2 is the revision that introduced the 12-pin FFC connector along with the separate VGA dongle PCB. On earlier integrated boards (v0.4 to v1.1) VGA comes off a 6-pin 1.25 mm JST header on the board itself, and v0.3 has its own VGA breakout PCB, so the dongle does not apply to either.
This is the standard VGA output dongle for the PICO9918. Stock varies by seller. Check Lectronz, Tindie and ArcadeShopper, the same three outlets that carry the boards.
The dongle connects to the PICO9918 via a 12-pin 0.5 mm pitch FFC cable: the same cable used by the Digital AV Dongle and the SCART AV Dongle, so one cable serves whichever dongle you have fitted.
See Hardware Setup for step-by-step cable connection instructions.
There are no active parts on the dongle. Its entire bill of materials is the FFC connector and the DE-15 socket, and its schematic runs RED, GREEN, BLUE, HSYNC, VSYNC and ground straight through between the two. The 12-bit RGB resistor DAC that produces the analog video levels lives on the PICO9918 mainboard, not on the dongle.
Important
Leave the configurator's Output → Driver setting on Auto when using the VGA dongle. Because the dongle keeps HSYNC and VSYNC as separate nets, boot-time dongle detection correctly reports "no SCART dongle" and selects the VGA driver. Forcing SCART instead produces interlaced RGBs timing that a VGA monitor will not display. See Display Output for how that is detected and how to recover a blank screen.
The dongle's DE-15 output follows the standard VGA pinout, so any VGA cable works unmodified. The signals below come from the dongle's own schematic (pcb/vga/pico9918_vga_v1_2_schematic.pdf); the contact positions come from the numbers moulded into the connector itself.
| DE-15 Pin | On This Dongle | From FFC | Standard Function |
|---|---|---|---|
| 1 | Red | 3 | Red video |
| 2 | Green | 5 | Green video |
| 3 | Blue | 7 | Blue video |
| 4 | (not connected) | - | Monitor ID |
| 5 | Ground | GND net | Ground |
| 6 | Ground | GND net | Red return |
| 7 | Ground | GND net | Green return |
| 8 | Ground | GND net | Blue return |
| 9 | (not connected) | - | +5 V from the host, for DDC |
| 10 | Ground | GND net | Sync return |
| 11 | (not connected) | - | Monitor ID |
| 12 | (not connected) | - | DDC data (SDA) |
| 13 | Horizontal sync | 9 | Horizontal sync |
| 14 | Vertical sync | 11 | Vertical sync |
| 15 | (not connected) | - | DDC clock (SCL) |
| Shell | Ground | GND net | Shield |
Note
Looking into the socket, pin 1 is the top right contact and each row counts leftwards. That is the ordinary rule for a female D-sub seen from its mating face, and the plug that mates with it is the mirror image. Plenty of published VGA pinout drawings put pin 1 at the top left without saying they are drawing the plug, so check which view you are reading before counting.
The five grounds and the metal shell are one net on the dongle, landing on FFC ways 2, 4, 6, 8 and 10: one ground immediately ahead of each signal, as the FFC pinout lays them out. The only two FFC ways the dongle leaves alone are way 1 (BOOT) and way 12 (+5V), because a passive adapter needs neither.
Pins 4, 9, 11, 12 and 15 are the DDC and monitor-ID pins, and all five are open, so nothing can read the monitor's EDID through this dongle. That costs nothing here: the firmware offers a single timing, 640x480 @ 60 Hz, so there is nothing to negotiate for.
| Property | Value |
|---|---|
| Resolution | 640x480 @ 60 Hz progressive |
| Pixel clock | 25.175 MHz |
| Line total | 800 pixels (640 display + 16 front porch + 96 sync + 48 back porch) |
| Frame total | 525 lines (480 display + 10 front porch + 2 sync + 33 back porch) |
| Sync polarity | HSYNC and VSYNC both active low |
| Color depth | 12-bit RGB (4 bits per channel, 4096 colors) |
| Connector | DE-15 (HD-15) female |
640x480 @ 60 Hz is the only VGA timing the firmware offers today: the configurator's VGA/HDMI mode setting has a single option, 480p60. The Digital AV Dongle runs from the same timing and the same setting.
- Dongles: all three dongles compared, and the FFC pinout they share
- Display Output: how the output driver is chosen at boot, and how to change it without losing your picture
- Hardware Setup: FFC connector and cable routing
- Digital AV Dongle: HDMI alternative on the same FFC interface
- SCART AV Dongle: RGBs alternative on the same FFC interface
- Video Output Modes: all three output paths in the firmware