Coolbaby RS-35 Flashcart compatibility mod

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OmDRetro
Posts: 20
Joined: Sat Mar 25, 2023 7:54 pm

Coolbaby RS-35 Flashcart compatibility mod

Post by OmDRetro »

Hello! First time in posting on this forum :D

I just wanted to share this revision of the Coolbaby RS-35 (The one with built-in games).
Lately, I've been trying to modify this particular famiclone so that I can use this as my cheap testbed for running homebrew via flashcart.
Despite adding another circuit to supply more power to the Everdrive N8 FAMI, I am still unable to power on the cartridge.
Others have been successful in running the nes version of the flashcart through a 72P-to-60P converter on the same model, but of an older revision that uses a 6v barrel input whereas mine currently uses a micro b port.

The famiclone works when powered on through the main supply(Vcc) and once I run additional power through the relay circuit I made, which is found in the first picture, it unfortunately yields no difference (Green screen output).

Here are some photos of it:

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lidnariq
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Joined: Sun Apr 13, 2008 11:12 am

Re: Coolbaby RS-35 Flashcart compatibility mod

Post by lidnariq »

Is there more than one epoxy blob ("Chip-On-Board") ?

are there any other parts visible at all? I only see three resistors and a bunch of connectors.
OmDRetro
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Joined: Sat Mar 25, 2023 7:54 pm

Re: Coolbaby RS-35 Flashcart compatibility mod

Post by OmDRetro »

lidnariq wrote: Sun Mar 26, 2023 9:42 am Is there more than one epoxy blob ("Chip-On-Board") ?

are there any other parts visible at all? I only see three resistors and a bunch of connectors.
Here are some photos of the front side. There's a rom chip in front "256P/N 22625 SCX"

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krzysiobal
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Re: Coolbaby RS-35 Flashcart compatibility mod

Post by krzysiobal »

Why do you think it is caused by lack of power? I have ZOGA NES clone and it also refuses to load Everdrive N8 while it works fine with my flashcart.

I haven't analyzed boot up sequence of Everdrive N8 but my guess is that this cartridge depends on some timing relationship that are not meet by every famiclone, for example:
* trying to sample data bus in the middle of CPU cycle (after some fixed time after M2 rises),
* trying to sample /ROMSEL during falling edge of M2 (in chip consoles & good old famiclones, there was slight delay between them, but in newest ones they might change levels in the same instant or even /ROMSEL before M2),
* other than 6 number of dummy CPU cycles before fetching RESET vector after powerup/reset
* I see your console has built-in flash memory with games that show up when no cartridge is inserted; if the console uses pins 45+46 or 48+49 to detect lack of external cartrridge, it probably wont work with everdrive
Image My website: http://krzysiobal.com | Image My NES/FC flashcart: http://krzysiocart.com
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Individualised
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Joined: Mon Sep 05, 2022 6:46 am

Re: Coolbaby RS-35 Flashcart compatibility mod

Post by Individualised »

I don't know much about the Coolbaby but if it is based on VT or other "NES+"/enhanced NES hardware and not standard Famiclone hardware that may cause compatibility issues with flashcarts.
OmDRetro
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Joined: Sat Mar 25, 2023 7:54 pm

Re: Coolbaby RS-35 Flashcart compatibility mod

Post by OmDRetro »

krzysiobal wrote: Sun Mar 26, 2023 2:00 pm Why do you think it is caused by lack of power? I have ZOGA NES clone and it also refuses to load Everdrive N8 while it works fine with my flashcart.

I haven't analyzed boot up sequence of Everdrive N8 but my guess is that this cartridge depends on some timing relationship that are not meet by every famiclone, for example:
* trying to sample data bus in the middle of CPU cycle (after some fixed time after M2 rises),
* trying to sample /ROMSEL during falling edge of M2 (in chip consoles & good old famiclones, there was slight delay between them, but in newest ones they might change levels in the same instant or even /ROMSEL before M2),
* other than 6 number of dummy CPU cycles before fetching RESET vector after powerup/reset
* I see your console has built-in flash memory with games that show up when no cartridge is inserted; if the console uses pins 45+46 or 48+49 to detect lack of external cartrridge, it probably wont work with everdrive
The cart's LED activity indicator turns on for a brief moment before absolutely doing nothing and someone else was able to run the nes version of the cartridge on the same model. From there I assumed it lacked power :? . I did however try running the cartridge through my Coolbaby RS-40 and I noticed the LED indicator stays on for a few seconds before entering the menu. It runs without fail on the RS-40 variant.
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aquasnake
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Re: Coolbaby RS-35 Flashcart compatibility mod

Post by aquasnake »

all about these famiclone carts:

waixing ---------------|
subor ------------------|-----coolboy---------coolbaby---------mindkids----------powkiddy--------bullyboy


mapper #19x -----------|
#16x --------------------|
#15,#242,#227,#178 --|
and more... ------------|-----mapper #176----(coolboy)----mapper #268--------------------------------------




:beer:


外星-------------------|
小霸王-----------------|------酷哥-----------酷孩-----------(无对应中文商标)-----霸王小子(早期)-----霸王小子(目前)
Last edited by aquasnake on Sun May 21, 2023 8:11 am, edited 1 time in total.
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aquasnake
Posts: 515
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Re: Coolbaby RS-35 Flashcart compatibility mod

Post by aquasnake »

all about these famiclones made in china

micro genius/dendy/pegasus----|
seniton-----------------------------|
subor-------------------------------|
and more--------------------------|-----coolbaby


UA:6527(P)+6538/6528------|
TA:02+03N(P)-----------------|
and more----------------------|------UM6561---------|
---------------------------------------- 1818P-----------|
-----------------------------------------and more-------|----------blob NOAC-----------------|
---------------------------------------------------------------------- VT:enhanced NOAC-------|-----------no 4-screen support, no ciram/cxram switchable, add extended registers at $4xxx




unfortunately, everdrive n8 also occupies these address range, which would lead to register conflicts and cause crashes
OmDRetro
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Joined: Sat Mar 25, 2023 7:54 pm

Re: Coolbaby RS-35 Flashcart compatibility mod

Post by OmDRetro »

This "mod" isn't needed anymore because of one flashcart. :D

Image

As for Krzysiocart's capabilities and workarounds, I've documented it here as a viewable webpage
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