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"MTX Plus+" Firmware

 

MTXPlus+ incorporates three classes of firmware :

 

ROM Operating System, hardware device support, etc., compiled from Z80 Assembler source code
PLD Typically, a GAL22V10, used for I/O decoding etc., programmed using a JEDEC compatible compiler
CPLD Used for complex logic and/or I/O decoding, programmed using Altera's Quartus II package.

The use of CPLDs is optional, my prototype CPU and I/O boards use them, but Martin has chosen to only use GALs on his boards. Should a PCB version of MTXPlus+ ever make it into production, to minimise the component footprint and hence board size/cost, it is likely that the design will only use CPLDs.

 

Location PLD Plus . . . Main Functions
CPU Board 1 x EPM7128SLC84, or
ROM, RAM, CTC, RTC chip selects
Memory address line decoding
Page Port
Clock dividers for PHI, PHI4, PHI8, Ck/32

3 x GAL

1 x

GAL22V10

2 x

GAL16V8
 

1 x

74HC273

2 x

74HC193
I/O Board 1 x EPM7128SLC84, or
I/O port decoding (keyboard, joysticks, printer, CF)
Keyboard drive lines
Keyboard sense lines, Printer Status
Printer Status
Printer Control
 

1 x

GAL22V10

1 x

74HC273

2 x

74HC244
1 x 74HC374
1 x 74HC74
1 x 74HC04
1 x EPM7160SLC84 Optional - PS/2 Keyboard Interface
Video Board

1 x

GAL22V10
1x GAL22V10
 
I/O port decoding (video, sound)
Automatic Wait State Generation for VDP

 

Additional details of the specific functions can be found by following the links on the menu on the left hand side of the page.

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