mo5-512k

MO5 512K Cartridge

Description

this cartridge is compatible with thomson MO5 64k cartridge it's not a exact copy of the original cartridge
but rather a rebuild from the manual
the $A7CB register controlling a MO5 64 cartrige is extended to permit the access to 512k of memory
without the 3 jumpers the cartridge is behaving as the original thomson MEMO5 cartridge
with the jumpers set the cartridge can address 512k or memory

Note:

The first goal of this board was to replace the original thomson board of 64K
with the use of modern chips it is easier to find a 128k or 512k chip than 64k
so I designed the 64k compatibility as the main feature and the extension
to 128k or 512k (dépending on the ram chip used AS6C1008 or AS6C4008) as goody.
Due to negative comment on forums saying that this extra memory is useless
I've listened this comments and removed the jumpers permitting to exploit
the extra memory.
As a few 512k board exist I let 512k test procedure and manual but eagle files are now for 64k boards

Control Register in $A7CB (without jumpers)

bits 0-1   bank number
bit 2      1 = ram visible
           0 = basic
bit 3      1 cartridge ram is readable and writable
           0  cartridge ram is readable and read only
bits 4-7   unused        

Control Register in $A7CB (with jumpers)

bits 0-1   bank number
bit 2      1 = ram visible
           0 = basic
bit 3      1 cartridge ram is readable and writable
           0  cartridge ram is readable and read only
bit 4-6    extend the bank number
bit 7      unused

PCB

the pcb can be ordered from oshpark
https://oshpark.com/shared_projects/e0GleW5L

Bill of Materials

• 1 x socket dip 32 600mil
• 3 x sockets dip 20 300mil
• 1 74LS273
• 1 RAM Alliance AS6C4008
• 2 GAL Lattice 16v8D
• 1 diode 1N4148
• 5 resistor 10k 1206
• 5 capacitor 100nf 1206
• 1 block of 3 jumpers

GAL programming

the GALS can be easily programmed with a TL866-II plus programmer
GAL-16V8D-AC7B is going in the horizontal socket (check the marking)
GAL-16V8D-MO512K is going in the vertical socket

GAL compiling

The .JED files are sufficent to build the board
they can be recompiled from the .VHD by using:
"Lattice ispLEVER Classic"

Build of the board

the easiest is to solder the component in the following order

1. 5 100nf capacitor (back of the board)
   
2. 5 10k resistor (back of the board)
   
3. 4 sockets<br
4. BC547B
   
5. 1N4148
   
6. jumpers
   

Test programs

the test program is on Daniel's web site: http://dcmoto.free.fr/programmes/test512k-mo5/index.html

Test procedure

follow the instructions in https://github.com/6502addict/mo5-512k/blob/main/MO5-512k/debug