Hi all.
How easy is it to add commands to osi basic for the multicomp 6502 8k rom image ??

Some pointers would be helpful as it looks like simply adding an entry to the token table ??

I got the source to compile but im looking to add a c64 style sys call and a monitor call.

Thanks in advance. Lee

Will this work on grant searles multicomp ??

After looking at the gal programs on Daryl Rictors site and the multicomp from grant searle i thought the easiest thing for me to do was start with the multicomp design....

So, I have drawn up a board based on the multicomp cyclone 2 board from ebay.
Added 2 sockets for ram -as6c4008 and a ...

Hi Vladimir,
I have a slight suspicion that you do it incorrectly sketched from somewhere

I can now see why you have said this, after trying to use WINCUPL i found your posts on here referencing the "FIELD" statement.But the ideas came from Daryl Rictor's website for me to use a GAL as a quick ...

Hi Vladimir.
You are very correct. I used my lunchtime today to download wincupl and using an atf16v8b gal i can do all the address decoding i think.

Will post sim acreenshot soon as i think i got this right now but never used wincupl or any pld before today :D

As learning digital logic and ...

Thanks for clarifying that chaps . Will look at alternatives to tying the outputs together.

I need to do some reading up

I guess i can do the adressing with just 1 more OR gate / ic.

Apart from the wired logic do you think the addressing is otherwise good ??

Lee

Using ac chips total delay should be less than 50ns at 5v ?

Unless i misread datasheets maybe ?

Lee

What if i used open collector ? 74ac05 instead ?

Lee

Hi Vladimir.

The address lines 8 to 15 connect to P

The links select IO page befor the 138 chops the page into 32 bytes x 8

FC00 is 1111 1100 on links
FD00 is 1111 1101 on links

Lee

Hi All,
Knocked up the memory map decoding schematic, What do you all think ?

Using the 521 not the 520 in the schematic......

ADDRESS LEE1.JPG

The jumper is obviously to select 16 or 32k ROM ...

ADDRESS LEE2.JPG

Welcome your comments :D

Lee
Please post your schematics in monochrome for ...

Hi All,
Knocked up the memory map decoding schematic, What do you all think ?

Using the 521 not the 520 in the schematic......
The jumper is obviously to select 16 or 32k ROM ...
Welcome your comments

Lee

Thanks for the great replies.

I have been giving this lots of thought over the last few days before posting on here.

Excellent point about the clock stretching Jeff as that hadnt occurred to me, So now im wondering if the IO chips need the main clock or can i supply a secondary clock to them ...

Thanks, Jeff, Vladimir.

Maybe i should start at 0.9mhz to ensure things start well.

Looks like i need to investigate how to ensure CS goes low before PHI2.

As a beginner and from what i have read it seems that the SID is 1mhz max, a la C64.
V9958 is 2mhz max
My 6522's are from ebay so assuming ...

Hi all.
Im thinking of building a 6502 system comprising of.....

W65c02-10mhz
Rockwell6522 . 2off
6850 1 or 2 off (1 for midi)
Sid (prob swinsid as got 2) 2 off
V9958 video......Yea can see this being a pig......

The problem is speed. The sid afaik tops out at 1mhz so im looking for a wait state ...