Hello everyone!

I am starting a new topic because I don't want to clutter the last one. A link back to the original is here:

viewtopic.php?f=12&t=6818

I just posted a link to this topic on the last one as well.

Anyways! Attached is my Version2 schematic in B&W PDF form, and two pictures of my 4-Layer PCB layout in PNG format. I'm using KiCad, so if anyone wants those filetypes instead, I can supply them.

I'm posting them here, mainly as an update, but also to see if y'all spot any glaring mistakes. I've been through it a few times, and will go over it a bit more before I send off for the boards to be made.

They should be the 10cm x 10cm size, which JLCPCB sells for $8 right now, so I am taking advantage of that. Once I get BoardOne running as expected, I plan on soldering it to BoardTwo with those expansion pins, making it 10cm x ~20cm.

Thanks to all of y'all who have helped me thus far! Hoping that V2 will work more often than just... sometimes.

Chad

EDIT:

This will be using the W65C02 with a single W65C22 for nearly all of it's I/O (hence the name of the topic). 4-Layer board, 62256 32K SRAM, 28C256 32K EEPROM (with option to write to it from this 6502), and using a 74HC688 and 74HC00 for address finding and glue logic. I'm planning on running it on a 1 MHz oscillator, and powering it through USB. Definitely nothing fancy here, doesn't even have a power switch or power LED. I put a small 'expansion' place on the top-right for fun, and I have a hole near-ish to the top-left to run wires through in case I need to do surgery. Each chip will be in a socket, and so I put the capacitors underneath the chips themselves if possible.

I also added a white-background PDF version of both boards. Likewise, looking at dimensions as I was gathering parts online, I found I needed more room for my polarized capacitor in the top-left corner. So I had to adjust a few things to make it fit.

Lastly, I already ordered the board to be printed. I'll let you know how things go whenever it comes in.

Thanks!

It's been a long time coming, but here is an update on this board.

Attached are two pictures. I *finally* soldered it all today (had to get a new soldering iron even!) and then put the probes on some VIA port lines. As you can see from the scope, it's doing something!

I can't do anything else with this board right now, I don't have a working EEPROM programmer. I just put one I had from my previous board onto this one. It's original function was to put some stuff on a 16x2 LCD through PA and PB lines. I cannot tell you if this is all working properly, but:

1) It did not blow up.

2) It shows activity.

3) Looks much cleaner, tighter, and better than my mess o' wires Further, these traces and vias were done by hand, so they look *ultra* pretty

Well, there ya go! Worked the first try, as long as I print the board.

Just and update, and perhaps the last one for this particular board. My next project is found here: viewtopic.php?f=12&t=6914

Thanks everyone! I really could not have done this without your help, support, knowledge, and patience. Have a wonderful night, Happy New Years!

Chad

Very nice! That hand routed traces do look nice, but routing by hand is such a chore! Is the 2x20 connector compatible with your current VGA_RAM project? Your scope traces look wonderful. Are you using the Amazon probes?
Bill

It was a chore. And I can't nearly fit as many chips on a board that way. Every board going forward is computer traced.

It is a 2x20 connector, but it's not designed with my VGA board in mind. It's primarily VIA PA and PB ports, along with other things needed for additional VIA's. I *could* attach it to an earlier version of my VGA board, but at this point I'm going to just directly write to it instead of going through a VIA because it's much faster.

Yep! Using the new probes These have little hooks on them which make it easier to clip onto things. Also they have this 1x / 10x setting on the side, which is weird. I was getting really small bumps at first, then I saw I didn't have the probe set correctly. Learning!

Attached is a picture of the next 6502 board I'm working on. It's almost a copy of this board, but with additional features:

1) PS/2 Keyboard connector.

2) Super Nintendo Controller port.

3) Using a 74HC154 for better I/O control.

4) Using a 74HC163 for variable speed (starting at 4 MHz this time).

5) Ability to use either the SST39SF040 Flash ROM or the 28C256 EEPROM with 3 simple solder-jumpers on the back side.

This will plug into the VGA board on the left side.

Thanks Bill I appreciate everything.

Chad

Chad,
Please send me a blank board of Single 6522 V2. Since I was involved with prototype version of this board and had witnessed its birth, I felt like a godfather. I want to build a V2 and be a part of its life.
Bill

Sure thing Bill, it'll be in the mail this week! Thank you for your continual help and support.

Chad

Chad,
Received your board in the mail, it looks great! Manual routing sure is pretty even though it is labor intensive. I like having power/ground pins by the prototype area. Instrumentation grounds for scope probes are always nice to have. A square pad for pin 1 would be nice to have, especially during trouble shooting session. I see DS1813 footprint is not right for MCP130 so I have to adjust the pin to fit. These are small nits, overall the board is well done.

It is quite easy to assemble. I assembled it in about an hour. I have all the parts except 62256, but I'll replace it with something faster. This board should run 8MHz, possibly 10, even 12MHz.
Bill

Update: When in doubt do the NOP test. populate the 74HC00, 74HCT688, 1.84 oscillator, W65C02 and fill a W27C512 with all '$EA', power up!

Current consumption is 27mA, address A0 is toggling with a period of 2.18uS (460Khz) and A15 is toggling with a period of 71mS (14Hz). Looking good!

Haha, well thank you Bill

Yes, I have learned to have extra GND and VCC pins in all kinds of places. Definitely helps when probing.

On this particular board I did away with the square pads because they were getting "in the way" of my manual routing. Well, a couple were, and I am picky about uniformity.

The DS1813 footprint is wrong for DS1813 as well! I had flipped it.

Oh, and I way over-did the polarized capacitor footprint. I was expecting a big boy, but obviously a little one works too

8 MHz, wow! The next one coming in I'll be attempting 4 MHz.

When I get the EPROM programmer, I will check out that NOP test.

Thanks for that Bill, looks great!

Chad

While searching for a suitable replacement for the 65256 RAM, I thought of VGAxRAM since currently we are having conversation about VGA display. VGAxRAM is a text-based VGA piggybacked on a RAM chip. It snoops a 4K block of memory (in this case it is locations $4000-$4FFF) and display memory content as 64x48 VGA text while memory at $4C00-$4FFF serves as font lookup table. It is a good diagnostic tool since all I need is 6502, EPROM, and VGAxRAM. The EPROM program initializes the font table and writes whatever data to $4000-$4BFF to be displayed on the monitor. Attached is an animated GIF of EPROM program writing data to $4000-$4BFF after the font table is initialized. There are quite a bit of delay between each character write so to show program is running.

You may be interested to know in this example the CPU blew past 7.37MHz, 11MHz, 14.7MHz and is running at 16MHz. It will not run at 18.432MHz, however.
Bill

That is incredible Bill! 16 MHz is WAY beyond my expectations! Thanks for showing me, very neat to see it running something like that.

Chad

I have things I need to be doing, but this is so much fun! I have about 5 more things I like to try with your hardware, but I'll stop with this animated GIF. This is "Maxtrix" ported from CRC65.

I will say that your hardware is definitely capable of 14.7MHz operation
Bill