BOB-4 is Decade's fourth-generation low-cost video information overlay module. BOB-4 lets your microcontroller or PC display text and vector graphics on standard TV monitors. With user-definable character sets, BOB-4 also supports bitmap graphics and multiple languages. BOB-4 generates background video on-board, or automatically genlocks to your video source and superimposes characters over the image. Printable characters and commands control BOB-4 through SPI or RS-232 style data links, much like a serial printer. BOB-4 links directly to most microcontroller chips and modules, including the BASIC Stamp. NTSC and PAL video standards are supported in a single product version. Field firmware upgrades are supported via PC connection. BOB-4 hookup is simple, requiring only serial data, video, and DC power connections for most applications.
The BOB-4 is Decade Engineering's low‑cost video information overlay module that can display text and vector graphics on standard TV monitors via a serial or SPI interface. It supports NTSC and PAL video standards, offers user‑definable character sets, bitmap graphics, and optional font memory expansion.
The document covers video modes (Local, Genlock, Automatic), electrical specifications, pin descriptions, system hookup, command sets, vector‑graphics commands, debugging protocol, compatibility with the earlier BOB‑3, default character sets and troubleshooting tips.
| Form factor | 30‑pin SIMM, 3.50 × 1.05 × 0.35 in |
|---|---|
| Weight | ≈0.35 g |
| Operating temperature | 0 ~ 50 °C |
| Power supply (main) | +5 VDC, 100 mA typical (150 mA min) |
| Fault‑current protection | 250 ~ 300 mA |
| Auxiliary output | +3.3 V DC, 6 mA max |
| Overlay resolution (NTSC) | 320 × 240 pixels |
| Overlay resolution (PAL) | 384 × 288 pixels |
| Internal font memory | 62 kB |
| Standard serial baud rates | 1200 – 153600 bps (8N1) |
| Logic output voltage | 3.3 V CMOS (except pin 20) |
| Logic output current | 8 mA max (16 mA on pin 15) |
| Default serial baud rate | 9600 bps |
An inverting RS‑232 hardware interface such as the ICL3232ECBN chip is required to connect the BOB‑4’s TXD/RXD lines to a PC COM port.
The default serial baud rate is 9600 bps.
BOB‑4 needs a regulated +5 VDC supply, typically 100 mA, with capacity for 150 mA or more and fault‑current protection up to 300 mA.