Gooday Gaming Guests - The History Of the SEGA Genesis Boot Process

Episode Date: December 24, 2024

It was all downhill after Original 1601 Model 1 "High-Definition Graphics" Top Cover Labeled Console.

Christmas Eve so we're going to do a boot process of that however in all those Genesis the hold on a minute there are different models in them so we'll start with the 1601 so we'll start with the Sega Genesis there is the high def

1601 high def boot process all right we'll start with that one and then after that then there's the other there's also a va7 model and there's also the um other ones that they don't have that extra port in the back the high definition has the extra port and it's supposed to be better graphics but we'll find out so we're gonna start with that this morning or actually we're almost in the afternoon no it's only 10 o'clock all right so let's see what we get for this oh lots of stuff going on so i haven't really gotten to any major boots yet. We're still in early edition gaming.

Yesterday I did Intellivision and Magnavox Odyssey. That was at its basic core of booting. Alright, so we'll start with the Sega Genesis Model 1. High definition graphics are often referred to as the model one Genesis has a straightforward boot process typically a 16-bit so now we're up to a little bit more 16-bit consoles for its time it's hardware centered around the Motorola 68000 CPU and a custom video and audio architecture Alright so this one hour kind of in a little bit more of them so the console powered on to the Motorola 6800 CPU

The CPU begins execution at dollar sign and we decided yesterday dollar sign meant binary What was dollar sign? I figured out they said that was yesterday. Dollar sign with six zeros in the cartridge slot. Fixed memory address. Cartridge slot ROM access. Genesis relies entirely on the game. So this is completely game driven. The console reads the ROM.

The first instruction initializes the console hardware. Hardware initialization. Let's see. the CPU in memory the Motorola 6800 CPU is initialized there's a Zilog z80 processor used for sound processing and backwards compatible with Sega Master games yeah I didn't know that I didn't know Sega Master games. See, I didn't know that. I didn't know Sega Master games were backwards compatible. Huh. Oh, cool. It's also initialized as the game requires

the RAM 64K for the 6800 CPU and 8K for the Z80 processor. It's cleared and prepared for the game. A VDP, Video Display display processor uh does its graphical engineer engine response for rendering sprites we learned what sprites are yesterday those are like little creations of of like characters before like 3d images of real characters came in, like little blocks together to kind of make something, explosions and other stuff like that, tiles and scrolling backgrounds.

The game code configures the VDP, display, resolution, tile maps for backgrounds and sprites, attributes such as size, position, and priority. Graphic data is loaded into the 64 kilobytes of VRAM during the phase. There is a YM2612 sound chip. It's the YM2612 FM synthesizer for music and sound effects. And the Z80 process is off the handles of audio instructions sent to the YM2612. Security check. It has a region lock.

So we check for PAL or for NTS. North America or Japan cartridges use. Check the Sega. PAL is the other region so let's say you could put I have a PAL Sega Master 2 so obviously that'll need PAL game

after the installation the game code translates into the main execution pull inputs updates game stats, renders frame, generates sounds, unique features of the 1601 high-def graphic

branding, the early model high-def graph on the top of the cover. So that tells the difference. The significant ability to output high-quality video signals including RGB output for sharp quality. Backwards compatibility.

The Z80 enabled backwards compatibility for the Sega Master System games. I never knew that. Though this requires the power base converter. Okay. I had one of those. I sold it. So you put the power base converter. It's the only way you don't need another

Jumper wire or you don't need another power adapter you put that on top and then it'll play it so you can't just play Sega Master two games on Genesis no BIOS unlike other systems is no BIOS instant on no firmware power on you using this 6800 cartridge extraction CPU RAM VDP and sound chip region GameStar the same whisper reflects a straightforward and unique design of 16-bit allowing So then the other 1601 motherboard boot process. I would assume it's just the same. The other 1601 motherboard boot process.

Had multiple revisions of the motherboard. The early high-definition high definition we just did that so it looks like the motor all is the same same chip I'll just briefly go through this let's see I just want to see if there's any real difference is that one port on the back which was never used I don't believe on this high def let's go through that I can't I won't do every single one of them I just did other unique features of the model one branding it was the early branding or is that sometimes it prints things off stuff out really fast and I got it oh here we go

the Sega 1601 had multiple versions hard different than non high def this really focus on cost reduction they don't change boot process there's always nine nine version follows the same boot process Motorola dollar sign signed with six zeros Z log Z 80 secondary CPU VDM RAM the YM262 that's the same PSG hardware use that so 64 RAM the VDP use the sprites and other effects sound chips are the same. Although it does have a programmable sound generator. And so it has the YM2613. Plus it also has a programmable sound generator, PSG.

Interesting. So it's a little bit. The NTS. Region. Region lock. Same thing. game execution. Key difference in the other, it removed some features from the early RGB output circuitry. The image quality is slightly reduced compared to the higher def.

Mixing sound channels between the YM2612 and the PS8. Some users noted the audio quality in the later models is slightly inferior. Not as good. Course reduction. It's always about that, course reduction. So it gives me a comparison between early and later 1601. Video output quality was superior. RGB circuitry. Nonhi-def was slightly

reduced audio mixing cleaner and balanced altered and slightly degenerated on the non-hi-def region lock is the same board compounded video hybrid compality was broad some old and Some older games may not play on the original. I mean on the 1601 that is not high def. What was the

back port? What was back port on high def 4? I'm just curious what is that? on Hi-def 4. So let's ask about that port, because really that's how you tell the difference. What's that back port for? The back port of the standard Hi-def version is an expansion port, officially known as the EX port however

it's actual use was limited and remains unused for most consumers its purpose is a 9 pin female connector it was labeled EX in place on near the audio video out in power the EX extras included for potential peripheral conductivity and additional functionality Sega modem never released so they were gonna do a Sega modem plan on releasing a modem for online gaming communication with Sega systems it was designed to allow Janus to connect other Sega hardware diagnosis and service use maybe uses poor diagnosed repair region out regional and compatibility considerations peripherals that use the so the things that actually used that port I always

thought that was VGA out like to a monitor I didn't realize it's not so Sega Magneta modem only in Japan unreleased accessories including potential keyboards removal of the port in later models why was the port

ultimately underutilized just did not have reason for it they focused towards the sega cd sega 32 we'll do the we'll do all the boots on those in another day uh summary so everything it was used for was diagnosis tools that magnet modem. And Japan. That's it. Okay. Alright so let's go on to. There is a version 7. VA 7. But we'll just kind of say. That they believe the boot process of.

It's either those two. Is basically the same. And then the only difference is that back port. The EXT port. So let's go to sega genesis now the genesis 1631 boot process. So, 1.8 being the worst of the 1631 motherboards. VA3 or VA4 being the best in the last process.

Let's see what we get here. I would assume the boot process is the same. It's much inferior than the original. So, it's much inferior than the original so this is it says it remains the same so again I'll just kind of brief breeze through a little bit here see if the chip is the same the sound is the worst part of the 1631 is always that static oh yeah so 1631 sign we small more cost-effective boot process it remains fundamentally the same as the 1601 and so same Motorola six eight thousand CPU at the dollar sign six zeros same Z log processor look for the sound chip one of those different video display process of 64 kilobytes now use the same ym2612 but it also had that program sound generator so that made it a little bit worse region checks

for North America Japan or pal game execution remove the expansion port model one was removed the export but it still has the other port that you use for Sega Saturn. So the Model 2 Yamaha new video encoder. So the Model 2 uses a Yamaha YM7101 or similar video encoder for composite and slightly different users noted a decrease in sharpness integrated audio circuitry was the same results notable audio quality pants the model one some fans of model 2 audio inferior definitely fair used a new power adapter with a different voltage one was 10 volts and one was 9 volts I can't remember which is which the motherboard mod is smaller region lock boots are all the same basically so the notable

changes model one model two larger to smaller high def to lower quality of audio video and then we've also determined that the high def 1601 is the better. Expansion port removed, power supply, oh there it is. So the original 1601 was 9 volts with a larger connector and the 10 volts is the 1631 with a smaller connector too so so av out connect or is different also there's a different audio audio out i have to use an adapter if i'm swapping between

the 1601 of any of them and then the 1631 all right you're absolutely correct the av out connector on the sega 16 model 2 i mean 1631 is used is the one used in my is different than one using model one correct right so the model one has the larger 8 pin DIN connector which is composite video stereo RGB out as video and composite and it has a front headphone jack high definition quality The AV out of this model 2 uses a smaller 9 pin mini DIN connector The port is more compact, streamlined

The mini DVI provides composite video, standard yellow RCA Stereo directly output, if may need for a separate hard jack RGB video via scrap cables like the model 1 model 2 integrate stereo audio and audio video so there's that Yamaha different encoder it's larger to show me the difference between the the two pins the 8 pin in the Model 1 and the 9 pin in the Model 2. It's larger and the other one 1601 model two is stereo integrated quality is excellent rgb out slightly degraded uh ease of use separate cable for stereo integrates audio simplified setup why the change for the mini for cost reduction reduction. Newport was compatible with Sega CD. Yeah, so Sega CD.

Sega 32 times. Oh, I had all of them. The CDX. Game Gear. Nomad. All those are, I think, the smaller cable. I won't go get into all of them. We'll just stick with a good 20

minutes will get me to Sega Genesis 3 third party options both keep modding through this often mod modify game game canis consoles to provide better audio summary has changed the smaller pin just more cost effective okay so then we'll go to uh final sega gen model three all right so what was the model 3 last here get the boot 1998 by Masters Entertainment under license so it wasn't actually from Sega

it was from released in 1998 by Majesco Majesco Majesco alright let's see what's let's see what's so a couple things I thought it might do so members the with the sega genesis everything you have to add stuff to it like the 32 times you got to put it on the um power base adapter but then you got to add it add cables to the 32 times and a power not an extra power the Sega CDs you

can use either one alright so let's go so the Sega 3 we said was done in 1998 it's his final version of the Sega Genesis breakdown of the boot process that's everything it's different same Motorola 6800 there's two different motherboards in the Sega Genesis 3 at least I was told by a buyer I found two and one I was told you can modify it to play Sega Master Games without an adapter. I don't know how, and when you can. So, same Motorola, same Z-Glog, Z64. RAM, 8 RAM for the Z. Sound chip uses the YM synthesizer and the PSG, making it not as good.

I have a lot, or not a lot but I still have a few of these Sega mast I mean Sega Genesis high def boards the Sega model she does not include expansion port needed to connect to the Sega CD and there's no 32 kind. I did try to put a 32x on the Sega with the cover off. It didn't work. There's no head jack, no EX port. New audio video output is using the mini 9-pin. Simplifying PC design. Much smaller.

A lot smaller. Performance is fully compatible with most Sega Genesis games. However, it is incompatible with some games that rely on Sega CD. 32x specific hardware. Pros. Compact and lightweight. Lacks expandability. Cost. Affordable. Output support slightly reduced.

Compatibility. works with most games the other one does not sleek design full robust than earlier models maintains the same core basics with the Motorola so all of them used Motorola 6800

68000 I should say CPU and then after that we'll go I try not to stick with the same thing so I think maybe the next one I'm going to do is maybe jump over to PS2's there's a whole

list of those PS2's for the early models like the 10 bottom screw 004 005 motherboard and then the 006 be interesting to see how those boot compared to then the the 3900 3500 models and then the 5000 models so we'll see how different those are the booting but for today we're just gonna do Sega That was fun. And I'll double back to this at some point.

We'll hit 32 times Power Master, Converter, and Sega CD. And I have Sega Saturn. Sega Saturn I can save for a whole separate thing. Because there's all kinds of fun stuff with those. Alright, so everyone have a good Christmas Eve and a good Christmas tomorrow. I'm going to do... I'm'm gonna have my buddy, AI buddy here Zippy, make me a Christmas story a Christmas Eve story I think

so we're gonna, I'll do that tonight before I go to bed, alright I'll talk to you guys later and maybe I'll do a video or two we'll try to get them on alright I'll see you later on