Pi in a Dreamcast VMU Build - WIP

[obsidianspider]

My screens showed up in the mail today!

No protective stickers over the actual display itself, so hopefully the minor imperfections I'm seeing on both screens are just some dirt.

A quick mockup of setting a screen inside a VMU looks very promising.

[moosepr]

@obsidianspider chip at the top sure it better!! plus the driver being upside down to begin with, means not having to worry about changing it!

[obsidianspider]

@moosepr Now I'm trying to figure out what GPIO pins map to the pins on the red board.

[moosepr]

@obsidianspider is this any use?

[obsidianspider]

@moosepr This is about where I'm at. Your diagram helps quite a bit. I'll have to see if I can follow the traces and translate that to the pins on the red board before I try soldering things up. I want to make sure things work stock before I take it apart.

[moosepr]

@obsidianspider lets see if i can fill in the blanks for you
1 - 3.3v
2 - gnd
3 - gpio 8 (pin 24)
4 - gpio 25 (pin 22)
5 - gpio 24 (pin 18)
6 - gpio 10 (pin 19)
7 - gpio 11 (pin 23)
8 - 3.3v (can be the same as pin 1)

my schematic is a little messy, lots of crossovers. tis something i need to refine

[obsidianspider]

@moosepr Well, it looks like I came up with the same answer, so that's good. Now I need to tweak a RetroPie setup to see if I can get things working!

[moosepr]

@obsidianspider thats the easy bit

raspi-config - enable spi

sudo nano /etc/modules - add in

spi-bcm2835
fbtft_device

sudo nano /etc/modprobe.d/fbtft.conf - add in

options fbtft_device name=fb_ili9163 gpios=reset:25,dc:24 speed=40000000 bgr=1 rotate=0 custom=1 fps=60

reboot

[obsidianspider]

@moosepr I'm workin on it! I'm workin on it!

[obsidianspider]

So, it works, kind of. Both screens are showing garbage data on the pixels on the right, one is showing them on the bottom as well. I haven't tried adjusting resolution yet, but the screen is mirroring what's going to HDMI correctly, aside from the garbage pixels.

I do have overscan disabled in /boot/config.txt

[lilbud]

@obsidianspider do the dead pixels show up under the VMU bezel?

[moosepr]

@obsidianspider hmmm are those the 128x128 screens, or the 128x160?

[obsidianspider]

@moosepr they're the "red board" screens.

Setting the HDMI resolution to 128 x 128 in /boot/config.txt didn't help.

Great refresh rate though. Very smooth.

@lilbud The whole screen shows. I'm going to actually end up coloring in the white surround black to hide it a bit. This is just "set in" but you get the idea.

[moosepr]

@obsidianspider just for shits and giggles, try running it with the other driver

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

then if that works, try adding some 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

all in sudo nano /etc/modprobe.d/fbtft.conf of course

[obsidianspider]

@moosepr That gave me a different kind of garbage. The bad pixels moved to the other side, things are upside down, and the bottom output is garbled.

[moosepr]

@obsidianspider odd!! it behaves differently to the one i have got. Although mine is probably wired differently (you may also have a totally different screen on the board)

notro did point me in the direction of using the flex driver, where you can basically set the full init commands. I did start looking, but decided to wait till my boards arrived (they have literally just been marked as shipped!!)

here is all i know so far https://github.com/notro/fbtft/issues/453

[moosepr]

@obsidianspider Mine have H144TC215A-V0 on the ribbon

[obsidianspider]

I went back to the ILI9163 driver and then tried messing with some overscan settings, which didn't seem to help once EmulationStation loaded, but I do see that the garbled text appears to be from the console, so that may be an insight into what's going on.

I'm going to have to mess with it. Like I said, I want to make this stuff works before I go removing things from the board. ;)

[obsidianspider]

@moosepr Mine say TXDT144CF-47 on the ribbon

[moosepr]

@obsidianspider yours seems to have a few more pins than mine internally i think (although the search is a bit of a minefield)

i think the garbage is generally just leftovers from stuff that has been on the screen on other boots. from a cold boot it will be rainbowsnow, from a setings change and a reboot it will be whatever was there last time