ASCII: 6502 internal organization

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Daniel

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Mar 19, 2021, 3:48:06 PM3/19/21
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I am creating a set of facts about the 6502 processor and created a
diagram of the internal organization of the chip taken from a
programming book. How do you like it? Recommend any changes?

For the reference image go to page 42 in the linked pdf.

Doc: gopher://gcpp.world/9/phlog/docs/Programming_the_6502.pdf

Here's the art: gopher://gcpp.world/1/phlog/6502Org

Thanks in advance

--
Daniel
Visit me at: gopher://gcpp.world

Eli the Bearded

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Mar 19, 2021, 4:24:02 PM3/19/21
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In alt.ascii-art, Daniel <m...@sci.fidan.com> wrote:
> I am creating a set of facts about the 6502 processor and created a
> diagram of the internal organization of the chip taken from a
> programming book. How do you like it? Recommend any changes?
>
> For the reference image go to page 42 in the linked pdf.
>
> Doc: gopher://gcpp.world/9/phlog/docs/Programming_the_6502.pdf

I'm not really a gopher user, but are there gopher clients that can
display PDFs? I'm guessing if I pointed lynx at that it would just
give me the option to download the file, and I'd have to view it
separately.

> Here's the art: gopher://gcpp.world/1/phlog/6502Org

That works in lynx. Some of the labels are missing. PCL / PCH are
Program Counter Low / High, right? Where low and high are not low and
high water marks (to show a range of memory), but low and high bit parts
for holding an address larger than a bus width, correct? And A0 to A15
are address lines, again unlabeled.

On a pure ASCII art level, I think I'd move the MUXes further to the
right and give them longer lines, so instead of

KEY: | | | | | |
| | | | :-------------: .___.
X,Y: INDEX | | | | |->| |
REGISTERS | | | :--------------------|->|MUX|->AL
| :------|----------------------------|->|___|A0-7
S: STACK | | |

Have, say:

KEY: | | | | | |
| | | | :-------------: .___.
X,Y: INDEX | | | | |--->| |
REGISTERS | | | :--------------------|--->|MUX|->AL
| :------|----------------------------|--->|___|A0-7
S: STACK | | |

Just so that they don't look so mashed together. In the same "not mashed
together" way, maybe move the whole KEY section below the diagram?

Elijah
------
any reason for only posting a gopher URL instead of the art?

Daniel

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Mar 20, 2021, 4:38:31 AM3/20/21
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Eli the Bearded <*@eli.users.panix.com> writes:

> In alt.ascii-art, Daniel <m...@sci.fidan.com> wrote:
>> I am creating a set of facts about the 6502 processor and created a
>> diagram of the internal organization of the chip taken from a
>> programming book. How do you like it? Recommend any changes?
>>
>> For the reference image go to page 42 in the linked pdf.
>>
>> Doc: gopher://gcpp.world/9/phlog/docs/Programming_the_6502.pdf
>
> I'm not really a gopher user, but are there gopher clients that can
> display PDFs? I'm guessing if I pointed lynx at that it would just
> give me the option to download the file, and I'd have to view it
> separately.

Sorry for the inconvenience. It didn't occur to me that fellow usenet
users wouldn't have familiarity with gopher.

>> Here's the art: gopher://gcpp.world/1/phlog/6502Org
>
> That works in lynx. Some of the labels are missing. PCL / PCH are
> Program Counter Low / High, right? Where low and high are not low and
> high water marks (to show a range of memory), but low and high bit parts
> for holding an address larger than a bus width, correct? And A0 to A15
> are address lines, again unlabeled.

The key labels for PCL/CH are on the second page, you'd have to scroll down
to see it. I was thinking about moving them to the middle, below the
drawing so that it fits on one page. I was afraid that you wouldn't see
them.

The labels are identical with what the book had.

Ultimately, what this is going to end up doing is comparing the 6502
processor with the 65C02 that'll be used on the upcoming Commander X16
project. Currently, I'm researching that processor as well.

> On a pure ASCII art level, I think I'd move the MUXes further to the
> right and give them longer lines, so instead of
>
> KEY: | | | | | |
> | | | | :-------------: .___.
> X,Y: INDEX | | | | |->| |
> REGISTERS | | | :--------------------|->|MUX|->AL
> | :------|----------------------------|->|___|A0-7
> S: STACK | | |
>
> Have, say:
>
> KEY: | | | | | |
> | | | | :-------------: .___.
> X,Y: INDEX | | | | |--->| |
> REGISTERS | | | :--------------------|--->|MUX|->AL
> | :------|----------------------------|--->|___|A0-7
> S: STACK | | |

I'll see if I have room to widen it. Gopher's really designed for 67
columns and I'm really close. I may able to tweak the drawing.

>
> Just so that they don't look so mashed together. In the same "not mashed
> together" way, maybe move the whole KEY section below the diagram?

I'll see if I can redesign the key to fit on one page vs two.

> Elijah
> ------
> any reason for only posting a gopher URL instead of the art?

By the time it occured to me to ask an opinion, the page was already
formatted for gopher output. Also, I use tmux with a multiple screen
split. Copy&paste goes across different screens making it difficult to
paste these drawings into another window. I'd have to paste one line at
a time. So I provided the link to save time.

Next time I create something I'll ask before formatting.

tom

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Mar 20, 2021, 8:12:11 PM3/20/21
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On Fri, 19 Mar 2021 12:48:04 -0700
Daniel <m...@sci.fidan.com> wrote:

> I am creating a set of facts about the 6502 processor and created a
> diagram of the internal organization of the chip taken from a
> programming book. How do you like it? Recommend any changes?
>
> For the reference image go to page 42 in the linked pdf.
>
> Doc: gopher://gcpp.world/9/phlog/docs/Programming_the_6502.pdf
>
> Here's the art: gopher://gcpp.world/1/phlog/6502Org
>
> Thanks in advance
>

Would you mind serving that over gemini:// as well? My gopher client
has trouble with encodings and non-text mimetypes.

colin randall

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Mar 21, 2021, 5:19:00 AM3/21/21
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On Saturday, March 20, 2021 at 8:38:31 AM UTC, Daniel wrote:
> Eli the Bearded <*@eli.users.panix.com> writes:
> > In alt.ascii-art, Daniel <m...@sci.fidan.com> wrote:

> >> I am creating a set of facts about the 6502 processor and created a
> >> diagram of the internal organization of the chip taken from a
> >> programming book. How do you like it? Recommend any changes?

> >> Here's the art: gopher://gcpp.world/1/phlog/6502Org

hi ... i used https://gopher.commons.host/ to view the above url

> I'll see if I have room to widen it. Gopher's really designed for 67
> columns and I'm really close. I may able to tweak the drawing.
> >
> > Just so that they don't look so mashed together. In the same "not mashed
> > together" way, maybe move the whole KEY section below the diagram?
> I'll see if I can redesign the key to fit on one page vs two.

> > Elijah
> > ------
> > any reason for only posting a gopher URL instead of the art?

also had a few suggestions ... unfortunatly took the liberty of swapping
about some bits already ... appologies in advance ... here's what i thought
(also incorporates Eli's suggestion of *Letting Daylight In*)
... hope it helps
123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789

<=- - - - - - - - - - 6 7 c o l u m n s w i d e - - - - - - -=>


INTERNAL ORGANIZATION OF THE 6502

._______________._______._________.
| | | | DATA BUS
-----------------------------------------.------------> (DB0-7)
^ ^ ^ | ^ ^ ^ | ^ | | | ^
| | | | | | | | | | | | |
| | | | | | | | | | _v_ _v_ _v_
_v_ _v_ v_| _v_ v v___| v___| \ \_/ / | |
| X | | Y | | A | | S |I| | PCL | | PCH | \ ALU / | P |
|___| |___| |___| |___|_| |_____| |_____| \___/ |___|
^ | | | | |
KEY: | | | | | |
`-----|--|---|-------|----------: .___.
X,Y: INDEX | | | | |--->| |
REGISTERS | | `-------|----------|--->|MUX|->ADDR LO
`--|-----------|----------|--->|___| (A0-7)
A: ACCUMULATOR | | |
| | | .___.
S: STACK POINTER | | `--->| |
| `-------------->|MUX|->ADDR HI
PC: PROGRAM COUNTER `-------------------------->|___| (A8-15)

ALU: ARITHMETIC-LOGIC UNIT

P: PROCESSOR STATUS

MUX: MULTIPLEX

AH/L: ADDRESS HIGH/LOW


--
.
._!__ __ __ .
/ _\/_ |_ \!_.
/ / 7 / /|
\ \_ _/ / \ .
\_//__/|_\_\!_.
|

colin randall

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Mar 21, 2021, 6:31:57 AM3/21/21
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hi ... i've made an error in the schematic ... there is no data-bus connection
to the 'I' flag of the 'S' register ... didn't have the pdf at the time
--
cjr


colin randall

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Mar 21, 2021, 6:40:54 AM3/21/21
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Duh! ... reading the manual properly shows '*I*' as a '*1*' being the 9th bit
of the Stack register always set to a 1
--
cjr

Daniel

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Apr 8, 2021, 3:04:43 AM4/8/21
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I'm just now getting around to reviewing your input. Thanks for
that. This is side stuff that I'm going to publish at a later time so
it's not a major priority but as always I appreciate the input.

The gyms are open again so I'm busy getting back into shape. That and
I'm flying around on the weekends travelling. Making up for lost time.

In the vain of creating ascii art I'm thinking of creating and releasing
an html page for download that'll show the entire commodore 64 mobo
schematic composed in ascii.

Naturally it'll be a side scrolling document. In your opinion, is html a
good format or would you recommend something different? I'd say text
file, but I'm afraid any reader would wrap the text or use a
non-monospace font that'd ruin the drawing.

I want to reference a monospace font on the html page that'll work
across platforms.

Daniel

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Apr 28, 2021, 8:49:55 PM4/28/21
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i recently foudn out what gemini is. Not sure how to do this yet.

colin randall

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Jun 8, 2021, 7:46:52 AM6/8/21
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Hi Daniel ...

one caveat i forgot to mention when altering a scematic layout
is that any text narrative for the scematic cannot be cut'n'pasted
without alteration

the reference page : https://www.w3schools.com/tags/tag_pre.asp
describes the STYLE CSS for the PRE tag of HTML as :
pre {
display: block;
font-family: monospace;
white-space: pre;
margin: 1em 0;
}
so if the element (DIV or whatever) that contains your schematic
has those settings it should work across all web-browsers.
a lot of HTML elements can also have scroll-bars with the
overflow: scroll;
type STYLE setting
another setting i find i use a lot is
line-height: 100%;
since it seems most web-browsers render text at 120%

hope this helps
Colin
--

Daniel

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Jun 10, 2021, 9:49:40 PM6/10/21
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Thanks for the tips. I may or may not do it. Seemed more like a
challenge than anything.

I'm interested in basic html with as little formatting as possible and
with as small a package as possible.

I'm toying with the idea of having a web presence via packet radio.
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