Need Help with VIC Hardware Diagrams

[Jeff-20]

I'm working on a presentation of sorts for the VIC. I am far from a hardware expert. In fact, I have very little idea what I'm doing here, but I gathered information from a wide range of sources and some contradict others. I hope a few of you can look this over and help me with corrections.

[srowe]

The memory map looks correct but as the addresses are in decimal I'll have to do some more checks.

For the I/O ports a couple of edits, "Serial SRQ" is redundant, all the lines in the serial port are. The ATN line is always an output (because the VIC is a bus controller).

The Y pin on the expansion port is an audio input, but only on the CR model.

[Jeff-20]

Thank you! So, just remove the word "serial" or add it to every serial line? Also, several sources (like the programmers reference guide) show ATN as "in/out". I'm sure they are copying from each other like I am copying from them, so this could be a mistake. Are you sure ATN should be out only?

[srowe]

Thank you! So, just remove the word "serial" or add it to every serial line?

On http://sleepingelephant.com/denial/wiki ... Serial_bus I just put "SRQ", "DATA", CLK" etc. but that's just my preference I guess.

Also, several sources (like the programmers reference guide) show ATN as "in/out". I'm sure they are copying from each other like I am copying from them, so this could be a mistake. Are you sure ATN should be out only?

Yes, all diagrams in books etc have in/out but the way the protocol is implemented in the KERNAL this line is always an output. Its purpose is for the controller (the VIC) to alert devices on the bus, the VIC cannot operate as a device. Of course because it is hooked up to a VIA port you can turn it into an input line, but then it would become something other than the ATN line.

[Jeff-20]

Oh, goodness. How could I have overlooked our own wiki? You had all the port info there. Thanks!

[Mike]

There's also a diagram of the VIC-20 memory layout, which I designed some time ago and put into a sticky thread in the Programming section.

Jeff - I see you obviously took that one as inspiration, alas you eliminated lots of information I had put in there.

Regarding the connector/chip pinouts: if in doubt, I always refer to scans of the User Guide, a copy of the schematics, and to the chip data sheets.

[Jeff-20]

There's also a diagram of the VIC-20 memory layout, which I designed some time ago and put into a sticky thread in the Programming section.

Jeff - I see you obviously took that one as inspiration, alas you eliminated lots of information I had put in there.

Regarding the connector/chip pinouts: if in doubt, I always refer to scans of the User Guide, a copy of the schematics, and to the chip data sheets.

Ah, I'm sure the side by side layout came from your chart (would you like a credit? ). I recall looking at multiple examples. But for my presentation purposes, I followed the Programmer's Reference Guide layout on page 115 for a simple visual. Do you feel anything critical is missing or in error? I'm sure one could go into any level of detail.

I added hex now.

[srowe]

Your 2332/2364 pinouts don't match those on https://ist.uwaterloo.ca/~schepers/roms.html

[Jeff-20]

Your 2332/2364 pinouts don't match those on https://ist.uwaterloo.ca/~schepers/roms.html

Great source! For some reason I thought the two chips had the same layout. I feel like some of the books I used were in error (but it's more likely I just copied wrong).

The new question, for me, is how important is this hardware information to a programmer? Should I even include it when talking about programming?

[Kweepa]

That's a lovely memory map! Nicely contrasts the various configurations.
As a geeky programmer I would put hex down the right hand side. I'd probably also flip it vertically so $0000 was at the bottom.

[Jeff-20]

That's a lovely memory map! Nicely contrasts the various configurations.
As a geeky programmer I would put hex down the right hand side. I'd probably also flip it vertically so $0000 was at the bottom.

Good tip! Done!

[srowe]

The new question, for me, is how important is this hardware information to a programmer? Should I even include it when talking about programming?

Unless you're designing a ROM to EPROM adapter (or something similar) it's not really that useful.

[Mike]

Hi, Jeff,

Do you feel anything critical is missing or in error? I'm sure one could go into any level of detail.

what you should include really depends on the scope of your presentation. Is it a broad overview about the computer, available software and its distribution form (cartridges, tapes - rarely disks), peripherals (including the TV set as normal video output device!); or do you cover programming aspects (contemporary vs. today's cross-development possibilities), BASIC vs. machine language (or others like C, Forth, etc.). When you include machine language, you should present a programming model of the 6502. Hardware capabilities should include that besides text mode (with the ROM charset or with redefined characters), a bitmapped graphics display is actually possible (contrary to what Wikipedia tells people). Even though the base machine has only 5 KB RAM built in (and another 1K nibbles of colour RAM), RAM can be expanded (and RAM expansions were also already available at that time, and were in use!). Etc.

As a geeky programmer I would put hex down the right hand side.

The original had hex by both sides.

I'd probably also flip it vertically so $0000 was at the bottom.

In such diagrams I prefer the addresses to be readable like in a book page. A book page you surely also do not read from bottom to top.

[Kweepa]

Speak for yourself!

In such diagrams I prefer the addresses to be readable like in a book page. A book page you surely also do not read from bottom to top.

I'd probably also flip it vertically so $0000 was at the bottom.

[Mike]

Is something bugging you?

P.S. I fixed my response to match your seemingly preferred posting style (which isn't mine).

Speak for yourself!

In such diagrams I prefer the addresses to be readable like in a book page. A book page you surely also do not read from bottom to top.

I'd probably also flip it vertically so $0000 was at the bottom.