Pi in a Dreamcast VMU Build - WIP

[ABrugsch]

@moosepr doesn't the pi display a spark in the corner when the supply voltage drops below 5v? or is that just full size ones?

[moosepr]

@ABrugsch i get that on my pi3, but have never noticed it on the zero. I think you can actually turn the power/voltage warnings off

As usual you can override the behaviour in config.txt if you understand the risks: avoid_warnings=1 removes the warning overlay. avoid_warnings=2 additionally allows turbo when low-voltage is present.

https://www.raspberrypi.org/forums/viewtopic.php?t=82373

[obsidianspider]

I decided to order some of those cheap charging boards. 10 for $4.58, including shipping. (How are they making any money on this stuff?!) They're coming from China too, but since I have to wait for my screens anyway, I might as well save a few dollars. Do I need ten? No, but for the price, if I ever build something else that needs a charger, I'll have it, and won't have to wait another month.

(Photo from eBay auction)

[moosepr]

@obsidianspider yeah they are handy to have around. The circuit is really simple on those, I did consider embedding one onto my GBz board, but the pricing is to good not to take advantage of those boards. They must be knocking them out by the million!

[moosepr]

@obsidianspider here is what I mean about the screen inversion

https://twitter.com/Pi0CKET/status/846422958964924416

With the chip at the top, you're kinda in the middle of the bad zone

[obsidianspider]

@moosepr I see what you mean. I guess I'll have to take a look at how things line up, but I plan on looking at it face-on anyway. Not to mention that you said that rotating things 180 degrees would have that weird chunk of the screen blank anyway.

[moosepr]

@obsidianspider yeah im working on that!! apparently its a known issue. going to have a play with the st7735 driver and see if i can make it work 128x128

https://github.com/notro/fbtft/issues/453

[obsidianspider]

@moosepr That'd be cool if you got the other one to work at the proper resolution. Apparently those red boards are set wrong and you have to trick them into behaving properly.

• This display:
• http://www.ebay.com/itm/Replace-Nokia-5110-LCD-1-44-Red-Serial-128X128-SPI-
• Color-TFT-LCD-Display-Module-/271422122271
• This particular display has a design error! The controller has 3 pins to
• configure to constrain the memory and resolution to a fixed dimension (in
• that case 128x128) but they leaved those pins configured for 128x160 so
• there was several pixel memory addressing problems.
• I solved by setup several parameters that dinamically fix the resolution as
• needit so below the parameters for this display. If you have a strain or a
• correct display (can happen with chinese) you can copy those parameters and
• create setup for different displays.
  */

[moosepr]

running on st7735r the screen is the right way round, but too tall

options fbtft_device name=fb_st7735r gpios=reset:25,dc:24 speed=40000000 bgr=1 rotate=0 custom=1 fps=60

(see the bar is not centred)

so if i add some screen size in there

options fbtft_device name=fb_st7735r gpios=reset:25,dc:24 speed=40000000 height=128 bgr=1 rotate=0 custom=1 fps=60

(the shape is better, but i have my hunk of garbage back)

[moosepr]

there is of course an easy answer!!!! go back to the original 'proper' driver and just flip the pi!!!

please excuse the cat hair!!!

[obsidianspider]

@moosepr What do you mean by "flip the Pi"? You're rotating the display output somewhere else?

Based on your findings, which driver is "better"? Considering we can get the orientation now working with the right resolution and with the pins at the top or the bottom.

[moosepr]

@obsidianspider if you add into config.txt

display_rotate=2

then it rotates the pi display 180 degrees

i think for now, the ili9163 driver is the winner, as the resolution is correct. rotating the screen is a solution for now, but it destroys the option of keeping the hdmi output as an option. i will see what notro can come up with. he is a bit of a legend when it comes to the tft's!!

[obsidianspider]

@moosepr No need for HDMI out on my builds (for now) so I think I know which driver I'll be messing with once things arrive.

[moosepr]

@obsidianspider i think after 2 weeks of china post, we will have a better fix :)

[celly]

@obsidianspider i'm following this as I'm a big fan of the DC system and would love to see you put your magic to it. I have 2 spare VMU's from my DC i can donate if you need.

[obsidianspider]

@celly Thanks for that, but I don't think I'll need to cut up yours. I ordered two blue ones for $6 each on eBay and they should be here by Saturday. I would have loved to have found a white one for cheap, but those are selling for a lot more, and most don't have the dust caps.

As an example, here's one for $15 but I really don't want to spend that much for something so tiny just to cut up.

[ABrugsch]

Yeah there seem to be an abundance of the translucent blue, green and a couple of other colours all BNIB doing the bay at the moment.

[obsidianspider]

@ABrugsch I have to wonder where they're all coming from since the Dreamcast was only produced until 2001. The ones I ordered are theoretically brand new in the box.

[moosepr]

@obsidianspider maybe they made way more than they needed. Or maybe we invent a time machine in the not too distant future, and go back and tell them to make more, so there are plenty left for pi related shenanigans

[lilbud]

@moosepr The things I could do with a time machine...