CoCo4 Page (PaPaZilla)
This could be fun! Click on photo to get full
size of 1006x610.
UNCHANGED:
Power Switch.
CPU, GIME, PIA's
Standard game slot. (position not exact as yet)
4 mounting holes.
VGA 10-pin bottom connector.
Keyboard connector type and general location.
CHANGED:
Board outline, increased in the south direction
about 3/4 inch and increaded in the west direction about 1/2 inch.
For now, an old-style analog section (coco-2).
No salt-chips. (where are you going to buy them?)
To add in an A/D converter
(8-bit) for 8-bit joysticks. (later)
MAX232 instead of op-amps and comparators for
bit-bang RS-232.
ADDITIONS:
1.) 2-megs - 2 each 1-meg simm sockets and interface
chip. (Lattice)
2.) 1 serial - (6551) 10-pin header - PC style,
DB-9, MAX232 RS-232 driver, oscillator 1.8432MHz.
3.) 1 parallel - (6821) 26-pin header - printer
port - PC style, DB-25.
4.) Extra 27c256 ROM socket - jumper selected.
5.) 4MHz - with on/off switch header.
6.) Fully decoded I/O space - with square-pin
headers, for you guys who like to hack, tons of 74F139's.
7.) Buffered CPU - address & r/w. Separate
buffered: local E, Q, and R/W, gameslot E, Q and R/W.
8.) 3-pin connector to Tandy transformer. 7805
and 7812 regulators.
One
7805 local, one 7805 just for the gameslot.
May
add 7912 for -12V.
9.) Most chips SMD except for PIAs, ROMS, CPU
and GIME.
MISSING:
1.) Old power-supply section.
2.) 128K RAM section & connectors CN4-CN6,
not needed.
3.) Black plastic I/O jacks section. Square pin
headers instead.
Aimed
at re-packers.
4.) RF metal can section and 8 volt regulator
and switch.
5.) Holes for mounting the metalized-plastic
RF bottom cover.
WANTED:
1.) Help with ideas.
What
do you want to see ?
Name
it ?
2.) Old, unused, not running coco-3's for parts.
