INapGPU: Text-mode graphics card, using only TTL gates
4 days ago
- #Vintage Computing
- #DIY Electronics
- #TTL Logic
- VGA resolution 800x600@60Hz (accessible 400x300), mono display
- 50x18 character display with support for up to 255 characters in charset, expandable to 4 charsets using a 1Mbit EPROM
- Built using 2 counters, TTL gates, EPROM, and SRAM
- Parallel interface compatible with Arduino, Z80, and other microcontrollers
- Total IC count: 21
- Supports Latin alphabet with Polish letters and Standard Galactic Alphabet
- Pixel clock at 20MHz, utilizing a 12-bit counter (though 4-bit counters are recommended for reliability)
- Uses M27C1001 UV EPROM (1Mbit) for character storage, reduced to 128kbit due to 1-bit memory usage
- Sensitive to environmental noise, with image distortion from nearby USB or oscilloscope cables
- Known anomalies include image glitching during writes, unclear characters, and strange background lines