Standardizing symbols for PCB mirroring pads

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tepples
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Standardizing symbols for PCB mirroring pads

Post by tepples » Sat Jul 04, 2020 2:47 pm

The topic New Famicom Shells (Available Now) by muramasa shows a board with "H" and "V" pads for nametable mapping without making it clear whether that means arrangement (as on Nintendo boards) or mirroring (as on some other modern unlicensed boards). Is it time to standardize less ambiguous symbols for mirroring pads on PCBs? Here's a proposal.
mirrortypesymbols.png
mirrortypesymbols.png (281 Bytes) Viewed 683 times
From left to right:
  1. Horizontal arrangement or vertical mirroring
  2. Vertical arrangement or horizontal mirroring
  3. 1-screen mirroring (second symbol represents a status bar)
  4. 4-screen VRAM

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tokumaru
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Re: Standardizing symbols for PCB mirroring pads

Post by tokumaru » Sat Jul 04, 2020 5:33 pm

I like them, except for the 1-screen one. A status bar is an implementation detail, it's not something intrinsic to 1-screen mirroring. Maybe you should just have the first name table with a solid outline and the other 3 dotted.

tepples
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Re: Standardizing symbols for PCB mirroring pads

Post by tepples » Sat Jul 04, 2020 6:59 pm

In the vast majority of cases of 1-screen mirroring (that is, not that one Major League game or Magic Floor), the mapper outputs a signal to switch between the two halves of backing storage for the nametable. I guess the point is to show them as independent maps with different content.

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tokumaru
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Re: Standardizing symbols for PCB mirroring pads

Post by tokumaru » Sat Jul 04, 2020 7:56 pm

tepples wrote:
Sat Jul 04, 2020 6:59 pm
I guess the point is to show them as independent maps with different content.
My interpretation was that you were showing an instantaneous capture of the entire scroll space of the NES (2x2 name tables), where blocks with actual memory mapped to them had solid outlines and mirrors had dotted outlines. In the case of 1-screen mirroring, only one name table is mapped at a time, so the other one wouldn't be visible at all in this space, hence why I though that a single solid square with 3 mirrors would be a proper representation of this - the other screen is just not visible. Also, it makes much more sense that the icon for "1-screen mirroring" depicts only one screen, because that's what you get really, only one at a time.

The other 3 icons show where the mirrors are, it feels weird to leave this information out of the 1-screen icon just because you want to show that there are 2 individual name tables available. If you feel like you absolutely need to show how much name table memory you have in total, in addition to how it's mirrored, then it might be a good idea to display that information some other way, to avoid any lack of cohesion across the 4 icons.

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tokumaru
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Re: Standardizing symbols for PCB mirroring pads

Post by tokumaru » Sat Jul 04, 2020 8:13 pm

If you think there's enough space/resolution to write something in the squares, maybe you could do this:

Code: Select all

+---+---+    +---+ - +    +---+ - +    +---+---+
| A   B |    | A |   :    |A/B|   :    | A   B |
+---+---+    +   + - +    +---+ - +    +   +   +
:   :   :    | B |   :    :   :   :    | C   D |
+ - + - +    +---+ - +    + - + - +    +---+---+
Or use letters only, really:

ABAB: horizontal arrangement, vertical mirroring;
AABB: vertical arrangement, horizontal mirroring;
A/B: 1-screen mirroring;
ABCD: 4-screen VRAM;

It's even simpler to refer to them if you use letters, otherwise you'd have to awkwardly describe the icons, or post pictures of them whenever you wanted to discuss the mirroring settings in boards using these symbols.

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tokumaru
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Re: Standardizing symbols for PCB mirroring pads

Post by tokumaru » Sat Jul 04, 2020 8:30 pm

It could also be something like this:
mirrortypesymbols2.png
mirrortypesymbols2.png (401 Bytes) Viewed 623 times

muramasa
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Re: Standardizing symbols for PCB mirroring pads

Post by muramasa » Sat Jul 04, 2020 9:56 pm

tepples wrote:
Sat Jul 04, 2020 2:47 pm
The topic New Famicom Shells (Available Now) by muramasa shows a board with "H" and "V" pads for nametable mapping without making it clear whether that means arrangement (as on Nintendo boards) or mirroring (as on some other modern unlicensed boards). Is it time to standardize less ambiguous symbols for mirroring pads on PCBs? Here's a proposal.

mirrortypesymbols.png
From left to right:
  1. Horizontal arrangement or vertical mirroring
  2. Vertical arrangement or horizontal mirroring
  3. 1-screen mirroring (second symbol represents a status bar)
  4. 4-screen VRAM
So for my boards I went with the Nintendo naming. I made that choice a long time ago and it has kind of carried on till now. I have considered updating it to say 'Vert' and 'Horiz'. One of the big concerns for me is keeping the space the jumper takes up small.

lidnariq
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Re: Standardizing symbols for PCB mirroring pads

Post by lidnariq » Sat Jul 04, 2020 10:23 pm

tokumaru wrote:
Sat Jul 04, 2020 8:13 pm
It's even simpler to refer to them if you use letters, otherwise you'd have to awkwardly describe the icons, or post pictures of them whenever you wanted to discuss the mirroring settings in boards using these symbols.
I've personally taken to calling them "A10", "A11", and ... well, maybe "Q" and "4". But I do think about these things from the hardware first, so I'm not convinced it's a good choice for anyone else.

calima
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Re: Standardizing symbols for PCB mirroring pads

Post by calima » Sun Jul 05, 2020 12:07 am

Tokumaru's pic 3 makes me thing it's some supermapper that allows you to arbitrarily position the second nametable in VRAM.

krzysiobal
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Re: Standardizing symbols for PCB mirroring pads

Post by krzysiobal » Sun Jul 05, 2020 1:25 am

My propositions:
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Fiskbit
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Re: Standardizing symbols for PCB mirroring pads

Post by Fiskbit » Sun Jul 05, 2020 1:53 am

Code: Select all

A B   A A   A A   A B
A B   B B   A A   C D
I don't want to have to think about what pictures mean. Yes, using letters is imperfect for single-screen, but it still clearly explains the idea and also matches our own wiki's representation.

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Bregalad
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Re: Standardizing symbols for PCB mirroring pads

Post by Bregalad » Sun Jul 05, 2020 2:04 am

tokumaru wrote:
Sat Jul 04, 2020 8:30 pm
It could also be something like this:

mirrortypesymbols2.png
I vote for this ! Great work Tokumaru.

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tokumaru
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Re: Standardizing symbols for PCB mirroring pads

Post by tokumaru » Sun Jul 05, 2020 9:07 am

krzysiobal wrote:
Sun Jul 05, 2020 1:25 am
My propositions:
Let's see: in the first two icons, the checkerboard means "mirror", but in the third it means "another NT"? What about the 4th icon, what does the checkerboard represent there? If the same element (checkerboard) has different meanings depending on the icon, then we run into the problem of lack of cohesion again, which's not good. Unless I'm not interpreting your symbols correctly.

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tokumaru
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Re: Standardizing symbols for PCB mirroring pads

Post by tokumaru » Sun Jul 05, 2020 9:31 am

Fiskbit wrote:
Sun Jul 05, 2020 1:53 am

Code: Select all

A B   A A   A A   A B
A B   B B   A A   C D
Yeah, the great thing about using letters only IMO is that we can easily refer to these mirroring configurations in written or spoken form.
using letters is imperfect for single-screen
It doesn't show that there is a second name table available, something that tepples considered important in his first proposal. What about using "N" (for "name table") as a stand-in for either A or B:

Code: Select all

N N
N N
It shows that the same thing is mapped to the 4 slots but doesn't give the impression that either name table is "hardwired" to those slots.

The downside of using 2x2 letters is that it takes more space on the board than just "H" or "V".

krzysiobal
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Re: Standardizing symbols for PCB mirroring pads

Post by krzysiobal » Sun Jul 05, 2020 9:34 am

tokumaru wrote:
Sun Jul 05, 2020 9:07 am
krzysiobal wrote:
Sun Jul 05, 2020 1:25 am
My propositions:
Let's see: in the first two icons, the checkerboard means "mirror", but in the third it means "another NT"? What about the 4th icon, what does the checkerboard represent there? If the same element (checkerboard) has different meanings depending on the icon, then we run into the problem of lack of cohesion again, which's not good. Unless I'm not interpreting your symbols correctly.
No, the checkboard means "different", like solid=A, checkboard=B

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