What if hardware mods (upgrades) and the like

Post by **Quzar** » Thu Jul 31, 2003 4:42 am

I once posted on this ( click link for original post http://www.dcemulation.org/phpBB/viewtopic.php?t=16391) and as i expected almost the entire first page was laughing, scoffing, and otherwise ridicule directed at my 'newbieness' it wasnt untill posters actually read what i wrote an looked it up that they realised what i was saying was possible, and now if the gracious mods allow me to (pleeeeease?) i would like to revive my previous thread in this new form, open discussion on what-if modification.

My opening thought will be the same as my original thread. The SH4 and SH5 are pin compatible, instruction set compatable, and supposedly totally backwards compatable. In theory, couldnt an SH5 be dropped in (after hours of meticulously soldering the seeminly endless tiny pins) to a Dreamcast, not to yeild any speed improvements but just to make it work?

In theory the only difficulty (other than the actual upgrade) would come in two places, the BIOS not liking the new chip which may not be a problem since it is supposedly backwards compatable and the timer. The serious one is the timer, which may react to the new clock speed of the SH5 by just self destructing, OR may force the SH5 into SH4 type running. One note, I'm not in any way implying a performance increase and this can also be read as not 'is is possible to...' but 'what would happen if i were to...' . I know that it is possible to do it, but would it work?

Post by **Quzar** » Thu Jul 31, 2003 4:49 am

Just a quick add-on: Currently there is no place dedicated to hardware upgrade etc, maybe this could stay on longer than my original thread to become a makeshift FAQ and thread for discussion of this class of hardware modding. It could end responses that were made out of stupidity like those initial answers to my original post. Little did those flaming me know that there was actually theoritical possiblility to the idea based on facts released by Hitachi. If this thread is allowed to continue, ill post links to information about the processor.

Post by **Quzar** » Thu Jul 31, 2003 5:33 am

Well just so as not to have to wait for a first post ill put some links:
This is a link to a press release on the SH5 addressing its backwards compatability:
http://www.eetimes.com/semi/news/OEG19990923S0024
This is a link to the SuperH(SH) site, formerly made by Hitachi then Hitachi&some other company then Hitachi made a daughter company which hosts a SuperH website: http://www.superh.com/home/index.htm
On this site are links to technical data, press releases and white papers.
This company, wasabi systems, makes a lot of stuff with embedded SH procs:
http://www.wasabisystems.com

Please someone with more technical knowledge, look at this and post educated answer.

bizzle · Post by **bizzle** » Thu Jul 31, 2003 5:34 am

I remember that discussion.. back when I first joined, almost a year ago..

You CANNOT replace the CPU for one simple reason. The way its mounted. The Dreamcast seems to be multiple layers.. and the CPU is mounted onto it, but the pins don't go all the way through.. just to one of the layers in the middle.

Considering its done like that.. you have to rip the thing off to remove it.. to put it back on.. well you can't.. There isn't really a way to solder it back on, without expensive equipment.. if there even is any.

Post by **Quzar** » Thu Jul 31, 2003 5:41 am

thanks Xylene, i didnt realise that. I think this should continue as a discussion into theoretically whether it is possible or not, not if a home user could do it. It leads to further questioning of the restrictions of hardware in the Dreamcast console and leads to ideas about lets say a DC2. Lets say i had a fab plant that bought the old equipment from Sega for DC fab and decided i wanted to make a suped up DC that would play all old games fine but could also do new things, if that were the case could my prototypes start off with a DC that is identical except for core proc?

Post by **Quzar** » Thu Jul 31, 2003 5:44 am

please dont try to kill this thread so soon after i created it =*(

bizzle · Post by **bizzle** » Thu Jul 31, 2003 5:44 am

If you have ever seen the buttom of the Dreamcast motherboard, you would also see there are no pins there, considering the pins from the CPU don't go all the way through.. I am going to look for some pictures I took when I was practicing soldering on the back of the board so you can see it.

bizzle · Post by **bizzle** » Thu Jul 31, 2003 5:46 am

Oops.. double post.. but here is the back of the motherboard. Ignore the wires..

Post by **Quzar** » Thu Jul 31, 2003 5:56 am

i have seen the mobo before but didnt notice that, mostly because i was never seriously considering buying an ultra fine tipped soldering iron and somehow getting an SH-5 and trying it , this is all just theoretically not for any kind of immediate, practical use. just look at the Treamcast(?) although illegal it is an example of the hardware being modified and reproduced. Now i understand they didnt actually change the dreamcast's core hardware but did take the essential components and modify the assembly to have built in screen sound etc.

Post by **Quzar** » Thu Jul 31, 2003 5:58 am

also can you PLEASE edit that post to not include picture but a link to the picture? please?

Pyrosurfer · Post by **Pyrosurfer** » Thu Jul 31, 2003 9:17 am

The pins don't stickout on the other sides, but there are these tiny (copper i think) brown things stick out on the back that are connected to the processor, ram, etc. Once its done resisting or whatever it will go back through one of the brown things to the other side. I'm pretty sure there are no inner layers, just connection points from the front to back. If you were very careful using a dremel you could leave the pins slice the old processor off then carefully solder the corresponding pins. If you were a very very good solderer you could do it, because the pins are labeled with letters and numbers. After that you would have to put a new bios chip in like Dan Potter did, and you would have to know a lot about programming a bios. Don't even try this though, because you will most likely fuck up soldering and cutting the chip off.

bizzle · Post by **bizzle** » Thu Jul 31, 2003 9:40 am

Soldering the pins would be impossible with a normal soldering tool.. when you put the chip flat on the board where it goes.. you cant get under it to solder it.

Post by **Quzar** » Thu Jul 31, 2003 9:47 am

it wouldnt need to be sitting like it should be on the board at least not for test purposes, you could have it seperated from board with wires or long pin stilts or such and run it disassembled...

Synlor · Post by **Synlor** » Thu Jul 31, 2003 3:10 pm

The dreamcast has multiple layers, I'm 99% sure. Many common electronic devices have more then just a 2 sided pcb. I remember reading somewhere its impossible to do it at home, because you need a super expensive machine to do so. Meh, you can ponder on teh theory all you want, but its sort of a waste of time. Its almost impossible to do, and even if you could manage to get it installed, there is no gurantee it will work. Buutttt, if you do get it work, whats the point? You'd be the only person in the world with it, so homebrew shit optimized for it will enver happen. And if it does give a speed increase, no games would be playable.

Post by **Quzar** » Thu Jul 31, 2003 11:41 pm

im not saying for it to be a huge thing, nor for their to be a point. The fact that you are reading this or answering to this means that you already have free time so why not spend more trying to help solve this meaningless question or just not and do something else, but dont complain

Post by **Quzar** » Fri Aug 01, 2003 12:09 am

I just got an email back from from Hitachi that ends this discussion sadly. =( Turns out there is no SH-5 model that is pin compatable with the specific SH-4 model used in the Dreamcast but that if there were the instruction sets are completely backwards compatable so if they were physically compatable then they would be swappable. Oh well, down here i will post the full e-mail (not to long)

I can answer your question, which is quite complex and involves both
CPU
architecture and specific device information.

1. The SH-4 is a 32-bit CPU with an instruction set branded as
SHcompact. The SH-5 is a 64-bit CPU that supports the SHcompact
instruction set and adds a new multimedia instruction set called
SHmedia.

This means that binaries written for SH-4 would run on SH-5. However in
the Dreamcast there are many peripherals and system components and
changing CPU is not really a practical option unless you have access to
the all the source code written by Sega. You could contact Sega but I
doubt they will give out this material.

2. Pin compatibility
The Sega Dreamcast was built with the SH-4 CPU and a set of peripherals
e.g. memory interface, UART etc. The actual device was manufactured by
Hitachi Semiconductor (now called Renesas Technology, see
http://www.renesas.com) but it is not for sale any more.

There is no version of the SH-5 that is pin compatible with the SH-4
device used in the Dreamcast so it is not possible to swap out the
chips.

Sorry that we do not have any better solution for you.
Best regards
Mark Jones
Business Development

Well at least this ends conjecture but.... what if??? Expand! ram expansion or maybe even practical mods like making DC smaller (especially large PS) or maybe something else. I dont want this to end, this could become a mini-faq for people to end posts asking questions like mine =) . Isnt it interesting that SuperH actually answered? I didnt think that would work hehe

Prophet][ · Post by **Prophet][** » Fri Aug 01, 2003 12:36 am

I'm suprised the tech support gave you a detailed answer

qatmix · Post by **qatmix** » Fri Aug 01, 2003 3:44 am

It would be interesting to look at modding a DC so that it had USB ports or a HD.

Post by **Quzar** » Fri Aug 01, 2003 6:34 am

Prophet: yes that is interesting especially since it was the not tech but the sales dept. "Buisness Development"!

qatmix: There is already a DC that has been modded to have a HD, do a search for it in the forms and as for USB, that would be interesting, maybe a usb-DCcontroller or usb-serial port(DC) adapters that would work with certain things like USB controllers?

bizzle · Post by **bizzle** » Fri Aug 01, 2003 7:04 am

The HDD is next to useless.