I don't mind so much about the speed. Its more of a questions how to make it fit on various systems without having to redo a lot of code each time. Since I am using C compilers I cannot rely on architecture specific functions like the 6502 BCD arithmetic.

A while ago I started writing a basic interpreter that should be portable to any system which can compile C code.
Before I started I looked on the web, and found a similar basic interpreter written in C, but the problem there was that it assumed that the program is stored in a array, and reworking ...

I can't find any info anywhere about the IDT7174 .

I built one for myself with a pic16f877 and 74 series 8 bit latches to hold the address while data is being written to the sram.

I wrote the VHDL code, and it barely fits in two cpld, xc95108 pc84 + xc9572 pc44, and three 64k 15 ns sram ic. I tried to rout it on a 5x10 cm board, but it just can't fit. Now I switched to a 7x10cm board and it fits. I still need to do some tweaking and checking before I can order the board, if I ...

I already did a CRTC board with the MC6847 + chroma gen, but I don't find it satisfying.
It requires dual port ram if you don't want artifacts popping when accessing video ram which complicates things. On the other hand I would like something that generates VGA because my little telly is tiny and ...

That would be ok if I only had 74ABT245 as siganl sources, other modules might have different characteristics.
I tried sending an email to unicornelectronics to see if they had them, but their mailbox is full.

Never mind, the mc6845 datasheet has a block diagram.

Previously I used video chips like the 6847, but now I am looking for something that can generate VGA signals too. According to the wiki page the 6847 can do that since it can adjust the timing.
I was looking for some example schematic on google, but I couldn't find any.

Can anyone recommend a schottky diode model that is easily obtainable and affordable in large quantities?
I prefer trough hole for now.

Edit: I need the drives for tristating the bus too, so I can have another device access the bus.
Please see attached for a suggestion.
74s1053_schottky_array_16 ...

Two things:

1- I think the clock select jumper is incorrect as one end goes to ground, shouldn't it go to "Eclk" on the 36-pin connector?
2- The W65C02 can put it's address and data buses in high impedance mode via the BE signal negating the need for the 245 drivers. However, you might need to ...

Can anyone recommend a schottky diode model that is easily obtainable and affordable in large quantities?
I prefer trough hole for now.

Edit: I need the drives for tristating the bus too, so I can have another device access the bus.

Something that would be of much greater concern would be ringing caused by the extremely rapid rise and fall rates of the '245 outputs.
Yes, that might be an issue. I'll try putting terminators on the other end of the bus to prevent that. Just not sure yet what would fit better, resistors or ...

In this new project I am trying to build a modular system out of 5x10 cm boards.
The reason the boards are so tiny is that large pcb-s are expensive, so I am trying to keep it tight.
I made a schematic for the CPU module, with bus amps, and what worries me is that the buffering might generate some ...

Hi.

I' haven't been posting for a while, but that doesn't mean I am not working on anything 6502 related anymore.
After my first 6502 run I decided to scrap everything and do it all over, but better.

I decided to give it another run, and this time it is all going to be built on proper PCB-s ...