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Other Portable Consoles => Other Game Systems => Topic started by: kfchow on July 22, 2019, 11:50:32 pm

Title: RS90 in a GBA SP shell?
Post by: kfchow on July 22, 2019, 11:50:32 pm
Found this on aliexpress.

https://www.aliexpress.com/item/32992382153.html?spm=a2g0s.8937460.0.0.5c152e0enndXOR

Looks like a RS90 in a GBA SP Shell.  Hopefully moddable as it'll be nice to have the same firmware running.

It'll be nice to play GBA games on the same form factor.
Title: Re: RS90 in a GBA SP shell?
Post by: v47 on July 23, 2019, 11:51:46 am
It's the G100 (https://boards.dingoonity.org/other-game-systems/g100-console/), as far as I know, it's very close to the RS-90 (https://boards.dingoonity.org/ingenic-jz4760-devices/game-g100-cheap-gba-sp-clone-issue/msg187866/#msg187866), but with a larger screen (https://boards.dingoonity.org/ingenic-jz4760-devices/game-g100-cheap-gba-sp-clone-issue/msg187856/#msg187856).

One G100 on its way to pcercuei, fingers crossed hoping the device will be hackable.
Title: Re: RS90 in a GBA SP shell?
Post by: pcercuei on July 23, 2019, 05:52:37 pm
In theory it is hackable, but I can't figure out how to make the LCD work, so unless I get help with that it won't happen.
Title: Re: RS90 in a GBA SP shell?
Post by: v47 on July 23, 2019, 06:07:59 pm
Well, lets hope you will then - pretty sure a $25 RS-90 with a larger screen (that can run NES/SNES without scaling) would make a lot of people quite happy.
Title: Re: RS90 in a GBA SP shell?
Post by: kfchow on July 25, 2019, 02:53:32 am
Thanks for the info guys.  I'll grab one anyway since its cheap.
Title: Re: RS90 in a GBA SP shell?
Post by: quadjfet on July 26, 2019, 01:31:13 am
It appears to be using an 8-bit 8080-style MCU interface. Pinout seems to be a direct match to this, or compatible: https://www.aliexpress.com/item/32379373893.html , judging from my probing, see end of post.

This looks pretty tasty, and MIT Licensed: https://github.com/stevstrong/Adafruit_TFTLCD_8bit_STM32/

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Counting pins on socket, starting from left
Measurements taken while displaying Mario Kart Super Circuit - single player game start options

Pin 1  - 3.3V constant.
Pin 2  - 0V constant
Pin 3  - 3.3 constant, noisy
Pin 4  - 3.3 constant
Pin 5  - 0V constant
Pin 6  - slow enable-type thing
Pin 7  - fast enable-type thing
Pin 8  - 3.3v
Pin 9  - noisy 0v
Pin 10 - noisy 0v
Pin 11 - noisy 0v
Pin 12 - noisy 0v
Pin 13 - noisy 0v
Pin 14 - noisy 0v
Pin 15 - noisy 0v
Pin 16 - noisy 0v
Pin 17 - data             //8 MHz
Pin 18 - data
Pin 19 - data
Pin 20 - data
Pin 21 - data
Pin 22 - data
Pin 23 - data
Pin 24 - data

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Title: Re: RS90 in a GBA SP shell?
Post by: pcercuei on July 26, 2019, 02:46:13 am
It is a 8-bit 8080 interface, yes. I think it's a ILI9338 (there's the "ILI9338" string in the firmware dump).
Title: Re: RS90 in a GBA SP shell?
Post by: quadjfet on July 30, 2019, 09:48:42 am
The controller has id 0x7789, likely an ST7789V. I can successfully draw to the display with the arduino library "mcufriend".

https://github.com/prenticedavid/MCUFRIEND_kbv

I think the panel is read-only, so you just have to force it. You can't rely on asking the panel what it is and then choosing a driver.

I modified the example "diagnose_TFT_support.ino". I changed the first call to

Code: [Select]
tft.begin(0x7789)
which was all that was required, after some experimenting.
Title: Re: RS90 in a GBA SP shell?
Post by: quadjfet on July 30, 2019, 08:30:20 pm
As discussed on IRC, the lcd in the RS-12 Arcade Mini is electrically and mechanically pin-to-pin compatible and runs with the same 0x7789 codepath from the MCUfriend library.



Title: Re: RS90 in a GBA SP shell?
Post by: pcercuei on July 30, 2019, 09:39:43 pm
What I'm missing is the reset line, do you know where it's connected?
Title: Re: RS90 in a GBA SP shell?
Post by: quadjfet on July 31, 2019, 12:27:01 am
It is connected to pin 110 on the JZ4725B package. (At least on the RS-12 Mini I have opened up in front of me.)

I could be off by +- 1 pin, since the pitch is so small, but I am fairly certain.


Notes from breadboard testing:

1. Running the MCUfriend sketch, the pin starts out low as the board is in reset. It twiddles a few times as the ESP32 comes out of reset, then stays high for the duration of the sketch.

2. Disconnecting the LCD's Reset pin from the ESP32 while leaving everything else connected, the pin's default state is LOW. The pin will be in the LOW state and module will not init if you leave this pin unconnected. I get the standard blank white screen.

3. Tying the Reset pin to HIGH results in a successful panel init and display.


At least with my current breadboard setup, it does not seem like this pin needs to be actively controlled.
Title: Re: RS90 in a GBA SP shell?
Post by: pcercuei on August 05, 2019, 03:33:49 pm
Could you check on which JZ4725B pin is the reset line connected on the G100?
I don't have a multimeter so that's very hard for me to figure out.
Title: Re: RS90 in a GBA SP shell?
Post by: quadjfet on August 05, 2019, 07:29:52 pm
See my above post.

 The aliexpress pinout I attacheds further up the thread is an exact match to this panel. Pin 4 on the LCD is the LCD_RESET (active low), it is connected to pin 110 on the JZ4725B package. JZ4725B_DS.pdf refers to this pin as "LCD_DE" . PD21 GPIO group D bit 21 . (page 16)

I'll be on IRC for a little while if you have more questions.
Title: Re: RS90 in a GBA SP shell?
Post by: pcercuei on August 05, 2019, 10:09:55 pm
Yep, you confirmed that for the RS-12, but it may have been different for the G100.
(but it's the same pin, confirmed on IRC)
Title: Re: RS90 in a GBA SP shell?
Post by: kfchow on August 23, 2019, 09:09:29 am
So i got this and mine doesn't turn on.  It has a red led when charging but the other led (which i assume is green) and the screen itself never turns on:(  Big black nothing.
Title: Re: RS90 in a GBA SP shell?
Post by: v47 on September 26, 2019, 09:24:44 pm
Ebay popped one of these with a discount code at me, and as it was less than $25 total, I've grabbed it, so now I'm on this train as well.

I'm guessing nothing interesting happened in the meantime?
Title: Re: RS90 in a GBA SP shell?
Post by: v47 on October 09, 2019, 04:35:52 pm
Ok, got my G100, and the screen is quite nice (but they really could go for micro USB instead of mini USB), really hoping for a cfw now.
Title: Re: RS90 in a GBA SP shell?
Post by: Qinti on October 10, 2019, 04:19:46 pm
Can buttons be remapped? Also, how does this compare to a Bittboy in terms of stability? I am aware a Bittboy has CFW, but other than the shoulder buttons, is there any advantage to having this?

Also, can you comment on the playability of the I closed emulators and if there is any screen tearing?
Title: Re: RS90 in a GBA SP shell?
Post by: v47 on October 10, 2019, 09:24:40 pm
Plays GBA/MD/NES/SNES/MAME fairly decently as far as I can tell, but performance is not going to be top notch, obviously. Compatibility is identical to the RetroMini with its original fw.

Good:
- really nice screen
- a $25 pricetag
- the shell format is quite nice

Bad:
- not possible to remap buttons, this will make a lot of games unplayable
- mini USB charging port
- no GB/GBC support

Overall, I wouldn't recommend it without cfw, which I hope will be available in the nearish future. Until then, the BittBoy is a much better choice, and not that much more expensive ($35 is possible if you wait for a sale).

With cfw, this will become the recommended entry-level device almost for sure.
Title: Re: RS90 in a GBA SP shell?
Post by: Qinti on October 13, 2019, 07:32:09 am
By button mapping, you mean SNES and MD games right? I saw that mapping was a bit funky. How about GBA games? Are the buttons correctly mapped? And if you say performance is like the RS-90, you mean frameskip, right?
Title: Re: RS90 in a GBA SP shell?
Post by: v47 on October 13, 2019, 01:16:33 pm
Yes. The default button mapping is slightly different from the RetroMini, and if it does not allow you to control the game properly out of the box, you are out of luck - the first victim being Chrono Trigger, no button will allow you to access the menu, and as you can't remap, you are done. The few GBA games I've tried seemed fine, but as always, your mileage may vary.

I'd say grab one if you like the format and it's $25 or less, stick it in the drawer and hope for the cfw.