[WORKING] Simple 6502 SBC from scratch (Deck65)

[GARTHWILSON]

There are so many manufacturers of these LCDs, and it's unfortunate that after all these decades, they still have not standardized on a pinout.  I don't think it has anything to do with China though, since I saw the problem in the 1980's when these things were mostly made in Japan and maybe Taiwan.  I made myself an LCD tester that accommodates various pinouts.  The 40x4 is sure nice though, and I like how you have it mounted above the board and its components.  There were also 80-column LCDs available in the tail end of the typewriter market when they made them so you could type a line and fix mistakes before it went on paper; but the availability was brief, as computers were coming within financial reach of the common household.

That tall, green ZIF socket is convenient, but I've had trouble with their lack of dependability.  Too often, there's a poor contact, and I have to release the lever and try again and again, or, when the EPROM is in there supposedly tight, I have to scoot it back and forth sideways so the scrubbing kind of cleans up the contacts.  I have never had that problem with the low-profile blue ones.

And again:  "Flashing" is what you do to memory that's flash memory, not EPROM.  EPROM is not flash.  You just program it.  You don't flash it.

[Sean]

GARTHWILSON wrote:

There were also 80-column LCDs available in the tail end of the typewriter market when they made them so you could type a line and fix mistakes before it went on paper; but the availability was brief, as computers were coming within financial reach of the common household.

My older cousin had a wordprocessor/typewriter like that. Some of those later word processors and 80's laptop-ish computers also featured some larger LCD's, and some of those were graphics-capable instead of just characters. The Tandy Portable Wordprocessor WP-2 of 1989 had an 80x8 LCD text display. The TRS-80 Model 100 did 40x8, and the Model 600 could do 80x16 text or 480x128 graphics. The Commodore LCD computer prototypes used the same resolution screens as the Model 600.

I suppose you can get more colorful graphical displays easily these days, but they may cost more in real-money terms now for similar resolution in a smaller form factor.

[drogon]

and3rson wrote:

EDIT: The major downside of writing in C for 6502 is that programs end up being huge: the 200-line C code of my (terribly unoptimized) Snake game compiles into a 3.5 (!) KB binary. Of course, most of it is juggling with software stack. Also, I could probably reduce it a bit by moving all helper routines (pushax, etc) into kernel and link them during C program compilation.
So yeah, CL65 is awesome, but it's nowhere near as good as a human writing in actual 6502 assembly. Looks like C only shines when it has plenty of large CPU registers to deal with.

On the other hand - "So what if they are large?" You have 32KB of RAM. Use it!

My C editor - about 1500 lines of C compiles to just under 16KB on my Ruby 65xx system. Works a treat. So use that RAM - you paid for it after all...

Great video.

-Gordon