Replica I video section information?

From: John Honniball <>
Date: Wed Feb 23 16:27:29 2005

Jim Brain wrote:
> Does anyone know where I could find technical information on the video
> section of the Replica I? (the ATMega8 and 74LS166 section)

I bet it's very similar to, if not exactly the same as, Daryl Rictor's
video generator circuit:

The 74LS166 is clocked by the dot-clock and loaded every eight pixels
from the Atmel AVR CPU, i.e. every microsecond. Do that 40 times, and
you have one scanline of the 40x25 display. Then, you generate sync
pulses with the AVR's I/O lines and a simple D/A convertor. The
firmware in the AVR counts scanlines, character rows, blanking periods,
etc., and also handles updates from an 8-bit parallel interface.

John Honniball
Received on Wed Feb 23 2005 - 16:27:29 GMT

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