Now I’m much more incentivized to get my Plus4 working properly again!

So I went back this morning with a clear head and did some more digging for datasheet information outside the standard Hitachi sheet and the minimal one for the LCD display that I had.

I stumbled on this version: http://web.alfredstate.edu/faculty/weimandn/lcd/lcd_initialization/lcd_initialization ...

I do have a 50ms delay right after I set the DDR and set the output register to zeros before I start twiddling bits to initialize the LCD. I’m going to spend some time with the data sheets and see if maybe my delays are too long. I’m just doing 50ms for all of them...

Going crazy trying to get this 4 x 20 Character display working. All I get are a screen full of blocks (well initially I get a single line, then it flips to a full screen) I tested on a 2x16 also and get the same results, so I think my issue is in my initialization code. Code is deeply taken from ...

As I look across different 6502 projects I see two different methods of connectivity for Character LCD displays. Some projects show them hanging off the ports of a VIA and some projects have them directly on the system bus with the enable being driven by address decoding.

I plan on using a 4 x 20 ...

So, I figured it out! In my effort to take some photos of the analyzer and show the difference between when it works and doesn't I noticed something peculiar that I was ignoring, but shouldn't have been.


When it *worked* with CE and OE grounded, I saw this on the anaylzer:


ADDR DATA ROMEN
FFFC ...

I've been redoing my memory map and decided to use a GAL for decoding, wrote up the CUPL code, programmed the GAL, hooked up some DIPs and LEDs and it works as expected. (GAL20V8B)

What's odd is when I have the GAL in place, system won't start. Logic analyzer shows OE and CE on the ROM (28C65BP ...

I got a hold of a Tektronix 434 O-scope for *FREE* today. It was knows as working when it was last used (about 3 months ago) but the guy I got it from couldn't locate the probes.

I looked on eBay and see lots of probes, but not sure if I need to match the probes to the scope, or can I use any 1X ...

Does anyone have a parts database for common 6502 parts for gSchem. I finally got it working on my mac and have made a few schematics->PCBs already with great success, would like to use it to start desiging my 6502 computer.

Does anyone have a recommended, relatively inexpensive EEProm programmer? I built the SALT programmer and have been putting in my programs with toggle switches. Educational... yes, but very tedious now that my programs are getting much larger.

It'd also be nice to have one that can program PICs ...

Has anyone implemented a hash or a linked list datastructure in 6502 (not 65C02) ASM?

I think the linked list itself would be pretty easy to put together (it's just a bunch of pointers that you can reference indirectly) but the hash table seem sto be a bit more complicated....

I'm still working on ...

Thanks guys! This is exactly what I was looking for. I'm very used to writing code so that others can read and understand what I'm doing (and not end up like the gentleman Garth discusses at the end of his post)

The reason I asked for you guys to look over my code is that there are standard ...

So I've been learning 6502 assembly, picking it up pretty quickly now that I'm writing my own code.

I wrote this "bouncing ball" program that the next step is to turn it into some kind of pong game, it runs in MK's 6502 simulator quite well, am looking for comments, critic, and suggestions.

http ...

So I think I goofed when I ordered my parts for my computer I'm building. I ordered everything TTL EXCEPT for my EEPROM.

Is there any suggested glue logic so that I can use this CMOS EEPROM, or should I just go find a TTL one to use instead....

From what I've read, since it *is* an EEPROM and ...

Thanks for the link, it's exactly the info I was looking for. Reminds me of when I built a Handyboard in college, build in small steps and test as you go, little successes help make the project go a little bit easier.