Board revision requests

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rv6502
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Board revision requests

Post by rv6502 »

Since a board revision was mentionned...
uze6666 wrote: Wed Oct 16, 2019 4:12 amI'm planning a new minor rev where I will correct all the annoying things from the past like too small pads and I'll probably remove that second regulator too since it's not even on the Portable anyway.
I have a few feature requests:

alternative micro-SD slot solder points. (maybe under, because why not if there's room)

digital RGB pins header between the MCU and the resistors: Put a 2nd row of holes between the current resistor ones so if someone wants the
header then the resistors can be assembled vertically through the 2nd row. I'm probably gonna take the resistors out and put them on a daughter board/headers to swap them out and try something if I have the time.

Labelling on the gamepad header pins [ + C L D - ] (Google-ing pinouts is easy buuuut...)

Label the underside for the EXT connector.

Optional micro/USB plug solder pads for power. (maybe under the SD card slot, I'm using the USBtinyISP to power it, a USB charger could handle it)

Flip Player 1 SNES gamepad connector 180 (I've considered cutting traces on mine to flip it, might still do it)

And this is falling into feature creep and I can't figure out how the traces would route buuuut ever since I got this cheap SD card + usb hub on my desk I've been wanting an SD card slot right in the middle toaster-style.
sIMG_2362.JPG
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sIMG_2365.JPG
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That last one is silly but I've been itching to 3D print a mini-snes-style case for it. And the SD card sticking out the middle like a cartridge would complete it (heck, could even print a cart-shaped cover for the SD card)

I'll probably have to flip the centre capacitors to the underbelly to clear space and bodge-wire a vertical SD card short-connector board, screwed into the top cover.

So a header for the SD card connector would be nice. PD6 isnt broken out, everything else can come from the ICSP6 header.

Maybe if the /CS pin was brought up to the 6-pin ICSP header as an extra 7th pin it'd allow for a clean daughter-board cable with a 8-pin connector.

Someone could then leave the SD card slot unpopulated, that leaves space for the 2x4 ribbon connector.

EDIT:
Don't forget the /hold pin on the SPI RAM socket.

EDIT:
If the two 3x2 ICSP headers were a bit closer together (making a 3x4 grid) we could have the option to install the connector to the underside by using the centre 3x2 without having to use a mirrored cable.

Code: Select all

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Code: Select all

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+ + +  bottom ICSP
+ + +  bottom
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Code: Select all

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+ + +  also top ICSP
+ + +  also top ICSP
Last edited by rv6502 on Sat Oct 26, 2019 7:46 pm, edited 2 times in total.
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uze6666
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Re: Board revision requests

Post by uze6666 »

Lots of interesting suggestions, but the revision envisioned was to be kept minor and compatible in layout with my current assembly guide (and fit the 3D enclosure design).
alternative micro-SD slot solder points. (maybe under, because why not if there's room)
I think it's a bit hard to solder and against the goal of my pcb but I'll check it out.
digital RGB pins header between the MCU and the resistors: Put a 2nd row of holes between the current resistor ones so if someone wants the
header then the resistors can be assembled vertically through the 2nd row. I'm probably gonna take the resistors out and put them on a daughter board/headers to swap them out and try something if I have the time.
I suppose this can be done easily, though is anyone really have a use for that?
Labelling on the gamepad header pins [ + C L D - ] (Google-ing pinouts is easy buuuut...)
Totally agree on this one.
Label the underside for the EXT connector.
Reasons?
Optional micro/USB plug solder pads for power. (maybe under the SD card slot, I'm using the USBtinyISP to power it, a USB charger could handle it)
MicroUSB could be a good idea, I'd have to see if the footprint could fit over the existing barrel jack.
Flip Player 1 SNES gamepad connector 180 (I've considered cutting traces on mine to flip it, might still do it)
I'll skip on that one since can't do without changing the 3D case & assy guide.
That last one is silly but I've been itching to 3D print a mini-snes-style case for it. And the SD card sticking out the middle like a cartridge would complete it (heck, could even print a cart-shaped cover for the SD card)
This I like since I had the same idea while working on early enclosure designs. Adding a header under the current socket is not an issue.
rv6502
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Re: Board revision requests

Post by rv6502 »

uze6666 wrote: Thu Oct 17, 2019 3:08 am Label the underside for the EXT connector.
Reasons?
SNES-like case: I want to put a tiny door under to still be able to access the flipped EXT port, gamepad headers, AV pins.

I use those ports for debugging/profiling.
P8192666-small.JPG
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I might flip the ICSP connector too but that's risky. I'd have to remember to use a flipped cable.
Will probably go for a 90 degree connector to the back side for that one.

I guess for myself I could make a full-blown dock breakout-PCB that the Uzebox in it's case would sit on top.
That'd be less error-prone and I can label all that.
uze6666 wrote: Thu Oct 17, 2019 3:08 am
alternative micro-SD slot solder points. (maybe under, because why not if there's room)
I think it's a bit hard to solder and against the goal of my pcb but I'll check it out.
It'd be an optional feature for those willing to try.
uSD sockets are still in the realm of hand-soldering with a $5 iron for someone with experience.

If the regular large SD slot is on the top side there isn't much danger.
If someone messes it up they can always fallback to the regular slot.

I was just thinking that the industry is slowly phasing out full-size SDs.
More and more it's a uSD with an adapter that's being offered.

If the board is being updated might as well be a bit pro-active on this.

Personally I like the large SD card better. I hate having to crawl under the desk to search for that darn uSD that flew right out.
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nicksen782
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Re: Board revision requests

Post by nicksen782 »

@rv6502: A little off-topic here but I really want to ask. What is it that you are making in that picture you provided? What does the Arduino Mega do an what is the circuit that appears on the breadboard between it and the Uzebox?

Revisions do not happen that often. It may be worth considering more than small changes.
rv6502
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Re: Board revision requests

Post by rv6502 »

nicksen782 wrote: Thu Oct 17, 2019 3:34 pm @rv6502: A little off-topic here but I really want to ask. What is it that you are making in that picture you provided? What does the Arduino Mega do an what is the circuit that appears on the breadboard between it and the Uzebox?
I was logging exact blanking timing from the hardware. The board between is a level shifter: The Uzebox is 5V and the Due SAM3X is 3.3V

Due setup as SPI slave, feed the pixel clock into SPI clock, feed the blanking signal to MOSI: A poor man's logic analyser.

And the green wire on the Due going to itself just forces it's SPI-slave chip-select /CS pin to ground so it gets the constant flood of SPI bits.

It was actually quicker to get the results than using a real logic analyser; exporting the data, then writing parser, all that work when instead I can just analyse it right off the Due board as I'm tweaking the Uzebox code.
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nicksen782
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Re: Board revision requests

Post by nicksen782 »

Clever! Are you making a new video mode?
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Re: Board revision requests

Post by CunningFellow »

rv6502 wrote: Thu Oct 17, 2019 3:57 pm I was logging exact blanking timing from the hardware. The board between is a level shifter: The Uzebox is 5V and the Due SAM3X is 3.3V

Due setup as SPI slave, feed the pixel clock into SPI clock, feed the blanking signal to MOSI: A poor man's logic analyser.

And the green wire on the Due going to itself just forces it's SPI-slave chip-select /CS pin to ground so it gets the constant flood of SPI bits.

It was actually quicker to get the results than using a real logic analyser; exporting the data, then writing parser, all that work when instead I can just analyse it right off the Due board as I'm tweaking the Uzebox code.
I love the work Jubatian did on the CUzebox emulator to show timing info as a colour line down the side of the screen. When ever I am working on a new video mode I just look at that now.

Prior I had a 2nd AVR running on the same 28.63Mhz clock as the first doing input capture on the syncs and sending out info about counts via UART at 57600. Obviously not all lines, but you don't have to send out anything on lines that are 1820 clocks long.
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Re: Board revision requests

Post by uze6666 »

Yep, same for me now, I mainly use cuzebox for timing of video modes. Though I sometimes also use the Atmel Studio simulator's cycle counter for optimization purposes.
rv6502
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Re: Board revision requests

Post by rv6502 »

Added to the first post: Don't forget the /hold pin on the SPI RAM socket.

Probably good to have a cut-able trace between that and VCC in case a different but almost-pin-compatible chip is used.

Just added the SPI RAM chip on mine, updating my VM to use it instead of trying its best to trash the SD card :lol:
rv6502
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Re: Board revision requests

Post by rv6502 »

If the two 3x2 ICSP headers were a bit closer together (making a 3x4 grid) we could have the option to install the connector to the underside by using the centre 3x2 without having to use a mirrored cable.
sIMG_2378.JPG
sIMG_2378.JPG (94.48 KiB) Viewed 14889 times

Code: Select all

+ + +  top ICSP
+ + +  top ICSP
o o o  
o o o

Code: Select all

o o o  
+ + +  bottom ICSP
+ + +  bottom
o o o

Code: Select all

o o o  
o o o
+ + +  also top ICSP
+ + +  also top ICSP

I've hacked up a header for the digital signal and a pin for the SD card's /CS signal.
sIMG_2379.JPG
sIMG_2379.JPG (98.35 KiB) Viewed 14889 times
That probably deserves it's own topic but I think it'd be possible to make an HDMI output add-on board, at the very least a cheap VGA scan doubler. (for whatever reason none of my TVs will accept 15Khz VGA, they'll take 15Khz-everything-else just fine, incl on HDMI, just not on the VGA connector :| )

I'm still looking at the options (custom FPGA or some existing solution like an ADV7524A + CPLD to convert the PWM audio back to 8bits)
VGA is definitely the easiest.
It's way down on my projects backlog for now.
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