Search found 53 matches
- Fri Mar 20, 2015 4:35 pm
- Forum: Hardware
- Topic: Model 1 MD PCB hacks topic
- Replies: 17
- Views: 38455
Maybe they forgot about them? I mean the VA6.8 *still* has them and the markings of 5402:VA5 | 5433: VA6, except it says V6.8 on IC BD M5.. text My Japanese MD1 says "IC BD M5" on the board, no VAxx. The VAxx is near the I/O + bus arbiter chip. Here's a picture of someone else's VA5: http://i721.ph...
- Fri Mar 20, 2015 3:54 pm
- Forum: Hardware
- Topic: Model 1 MD PCB hacks topic
- Replies: 17
- Views: 38455
- Fri Mar 20, 2015 1:54 pm
- Forum: Hardware
- Topic: Model 1 MD PCB hacks topic
- Replies: 17
- Views: 38455
MD1 VA5 and VA6 have the exact same PCB. What make a VA5 (exactly as it's written on the PCB) is the I/O + bus arbiter chip be 315-5402. The slightly different copper you mention is a Asian model which has built in RF modulator. That makes it look very close to the "EXPORT" (aka European/USA) models...
- Sat Mar 14, 2015 6:33 pm
- Forum: Hardware
- Topic: Model 1 MD PCB hacks topic
- Replies: 17
- Views: 38455
I made these pictures from my VA6 Japanese MD1: https://lh6.googleusercontent.com/-91PKWr6aUlY/VQR7x7_G2UI/AAAAAAAAIVo/4clIYPkcW9Q/s800/DSC02473.JPG The green wire links VDP pin 119 (/RAS0) to the /CS pin on both of the PSRAM chips working as the CPU work ram. Yellow and blue on the other side are t...
- Sat Mar 14, 2015 2:51 pm
- Forum: Hardware
- Topic: Model 1 MD PCB hacks topic
- Replies: 17
- Views: 38455
I know this post is old... But you deserve a reply. The 220 ohm resistor on /AS at the 68000 is put when the console is using a FC1001 VDP (315-5313A) with a Motorola CPU. When the CPU is Hitachi CMOS HD68HC000, like this one: http://www.retroisle.com/others/segamegadrive/Pictures/images_technical/M...
- Mon Jan 12, 2015 1:54 pm
- Forum: Mega/SegaCD
- Topic: MegaCD2 Japan Bios on PAL MegaCD2
- Replies: 23
- Views: 36265
Apparently KRIKzz is unaware of the HINT stuff (register $A12006 and vector $000070) thus Mega Drive everdrives glitch a lot on CD stuff:
http://krikzz.com/forum/index.php?topic=1936.0
http://krikzz.com/forum/index.php?topic=1936.0
- Mon Jan 12, 2015 3:03 am
- Forum: Mega/SegaCD
- Topic: MegaCD2 Japan Bios on PAL MegaCD2
- Replies: 23
- Views: 36265
This is the simplest I could get with the parts I have here: https://lh6.googleusercontent.com/-EmabhILEvbo/VLNC74PrZhI/AAAAAAAAIEw/2m3esuARsfs/s800/mega-cd_bios_from_cartridge.jpg Tomorrow I'll assemble that and debug/change if there's any mistakes with address decoding. For now I found out a few g...
- Sun Jan 11, 2015 6:34 pm
- Forum: Mega/SegaCD
- Topic: MegaCD2 Japan Bios on PAL MegaCD2
- Replies: 23
- Views: 36265
https://lh4.googleusercontent.com/-JR-L-0MKPlw/VLLBBe1IFZI/AAAAAAAAIDw/AX-Yrdu4rsM/s800/mega-cd_bios_from_cartridge.jpg (wip) I am still working on the logic which toggles /CART HIGH when the HINT vector is read so the MCE chip has control of HINT address. (that's what the 7430s being drawn will do...
- Sat Jan 10, 2015 3:08 am
- Forum: Mega/SegaCD
- Topic: MegaCD2 Japan Bios on PAL MegaCD2
- Replies: 23
- Views: 36265
Not really, my Mega Drive is a VA3. And I'm going to only test patches and the translation of the Japanese BIOS to English I wanted to do since forever ... lolTmEE co.(TM) wrote:Now I see how it would work, I had a brainfart.
You will have to deal with TMSS first though, otherwise it gets in the way.
- Sat Jan 10, 2015 2:16 am
- Forum: Mega/SegaCD
- Topic: MegaCD2 Japan Bios on PAL MegaCD2
- Replies: 23
- Views: 36265
- Sat Jan 10, 2015 1:35 am
- Forum: Mega/SegaCD
- Topic: MegaCD2 Japan Bios on PAL MegaCD2
- Replies: 23
- Views: 36265
There is a bit in the config register of the everdrive thats set when a BIOS is flashed to the everdrive, so maybe the fpga traps addresses 0x20000 - 0x3ffff and 0x200000 - 0x23ffff and sets CART_IN high when in this range. That gave me a idea for testing modded CD BIOSES without opening the Mega C...
- Tue Dec 30, 2014 5:56 am
- Forum: Megadrive/Genesis
- Topic: Machine Lock-up
- Replies: 5
- Views: 5014
- Sat Dec 27, 2014 11:12 pm
- Forum: Mega/SegaCD
- Topic: Custom BIOS from cart
- Replies: 4
- Views: 13101
- Sat Dec 27, 2014 7:46 pm
- Forum: Mega/SegaCD
- Topic: Testing boot from CARTRIDGE SLOT at 0x400000
- Replies: 14
- Views: 26416
A few hours more of work poured on this: Euro ROMs do consistently use the same security data as the CD. You can make a single cart which will boot on any un-modded PAL system out there. That's a good thing. For USA consoles things are a little grim: The tray model SEGA-CD with BIOS 1.10 use the sam...
- Sat Dec 27, 2014 3:03 pm
- Forum: Mega/SegaCD
- Topic: Custom BIOS from cart
- Replies: 4
- Views: 13101
For debugging purposes I'd like to suggest: This boot method: http://gendev.spritesmind.net/forum/viewtopic.php?p=14320#14320 Coupled with some RAM on cart and some hardware for uploading cross development builds being tested. The cart could be something like this: 0x400000-0x40FFFF SEGA security co...