The most up-to-date board revision as of 5/29/2017 is 1.0-003. The Bill-Of-Materials below reflects a number of chip substitutions:
- Two of the 74LS244's are updated to 74ACT244 logic; one is unchanged
- Two of the 74LS374's are updated to 74ACT374 logic
- C1, 22uf on the schematic, is updated to 100uf or larger.
- Two 10uf Tantalum capacitors are substituted at C9 and C11.
The GAL chips are both ATF16V8BQL-15PU. The 15ns speed is important. Slower and faster GALs have led to unreliable operation. The -BQL suffix is the lowest power version.
Layout Indicating updates:
The Programmers' Reference Manual is primarily for system programming at the BIOS level. Direct memory-mapped updating of display memory operates in a fashion identical to that of the IBM MDA/CGA/EGA/VGA adapters.
The test program ZIP file contains a tarball of the source, which includes a number of font files. The ZAP fonts are used under the GPL 3.0 license.
The schematic does not reflect the component substitutions specified in the BOM. Several components require update to faster versions.
|VGA3-Programmers' Reference 1.1||333kb||15-May-2017|
|VGA3 Test Programs||355kb||24-Jul-2017|
|VGA3 Schematic 1.0-003||493kb||31-Jan-2015|