archive.worldofdragon.org

Remember I had to make my own from resistors
Not an expert but I think the 'dot' is pin 1.

Did you really buy 100? I only bought 30!

It was buy 100 or 200 I do have a lot but if someone might need some I could sell them.

I want to try or want to use rom cartridges threw the expansion header but there is no CART/. I like to know how to add it? Anyone have any idea?

Here is the schematic.

A bit of extra decoding is required to put a cartridge ROM into the unused part of the memory map at 8000-9fff

The easiest way I can see is by feeding E, RW, A15, A14 & A13 into an LS138 decoder to generate the OE signal for the ROM. You can even get a couple of bonus signals that are active during writes to 8000 and c000 if you wanted for example to add a couple of registers for general outputs.

e.g.

I'm not not sure if I understand. I know the input pin 1 (A) R/W, pin 2 (B) A14, pin 3 (C) A15, pin 4 (nG2A) 0V, pin 5 (nG2B) A13 and pin 6 (G1) E but the output I don't understand what do they hook up to?

UPDATE:

I want to play dungeons of daggorath threw the expansion header but there is no CART/.

Y5 is the output you want to use as the missing /CART. This would go to the output enable and/or chip select of the external ROM. The other LS138 outputs are not necessary, but possibly useful for other projects.

Regarding playing Dungeons of Daggorath, if you're talking about the original game on cart, then it sounds like there may be a fair amount of work ahead of you, to modify the source code to work with the address map and I/O of the SBC, plus rework the graphics to a terminal-friendly format. It would be pretty cool if you did though!

I think I understand now. I will need to add 74LS138 to the circuit to get /CART and then add Y5 to expansion header.

sorchard Thank you very much.

I receive a e-Mail today and JLCPCB is shipping my PCB Board I order shipper is DHL so maybe next week.

@ noggin32 or anyone,

What program do I need to view it on a Laptop threw the RS232 USB?

You can use any Terminal software. I used Putty. Old versions of Windows had HyperTerm built in.
Baud=115200

It's a little unreliable as there is no handshaking. Fine for typing but if you paste a basic program it will have errors.