"Let's make GD ROM emulation happen" Facebook group.

[RetroJunkie]

Maybe that's where I went wrong! *eyes dart side to side* Yeesssssssssssssss
Pretty sure I went the chisel route, not sure I had decent desolder braid at that point...
Well that and that I was possibly soldering a completely incompatible chip in...
If I were to have the need to try it again though, I'd definitely give it another go!

[bennydiamond]

I find wick to be useful only when you want to fully remove solder from solder pads. I tried using the flooding technique but you have a big chance to end up with an unreachable solder bridge between 2 pins deep under the bridged pins. Then you start to try and bring it up front but you'll put alot of heat on those 2 pins and depending on the component you could damage it.

I've seen alot of people who brought boards with this and most of the time I ended up removing the chip, clean the solder pads then put it back on the "traditionnal" way.

And it's true that bigger soldering tips do the best job! Really pointy tips won't hold small solder drop onto the very end of the tip.

[TriMesh]

I find wick to be useful only when you want to fully remove solder from solder pads. I tried using the flooding technique but you have a big chance to end up with an unreachable solder bridge between 2 pins deep under the bridged pins. Then you start to try and bring it up front but you'll put alot of heat on those 2 pins and depending on the component you could damage it.

That's just practice, though - if you end up with any significant amount of solder on the part of the lead frame that's not lying on the board you're doing it wrong. I used to not like that technique too - until one of the technicians I was working with showed me how to do it right - basically, you have to be fast, and use the inside edge of the chisel bit to keep the solder away from the inside of the lead frame. This guy was soldering 0.5mm pitch 240 lead QFPs and taking about 2s to put the solder on each side. Then when you wick off the excess you put the edge of the wick up against the bend in the lead and apply the heat there.

I watched him build 20 protos like that (in addition to the big QFP, there were a couple of smaller ones and some TSOPs), and he didn't leave a single solder short on the board - I'm not pretending to be that good, though

[-=FamilyGuy=-]

And it's true that bigger soldering tips do the best job! Really pointy tips won't hold small solder drop onto the very end of the tip.

A good really-fine tip that holds solder is *priceless* though! Maybe not to solder chips with lots of legs, but for R or C that are very small; or a wire to a small via.

[TriMesh]

A good really-fine tip that holds solder is *priceless* though! Maybe not to solder chips with lots of legs, but for R or C that are very small; or a wire to a small via.

A fine tip is also very useful for initially soldering parts down - These are the two I normally use, and between them can handle pretty much any job without having to change tips.

irons.jpg

[bennydiamond]

A good really-fine tip that holds solder is *priceless* though! Maybe not to solder chips with lots of legs, but for R or C that are very small; or a wire to a small via.

I must admit that the fact you point out is so true.

Maybe it's because I haven't invested in a really high quality tip that I found them to be more messy than anything else. I should hunt down one of these.

[-=FamilyGuy=-]

Maybe it's because I haven't invested in a really high quality tip that I found them to be more messy than anything else. I should hunt down one of these.

Yeah, I'm lucky enough to have free access to a badass soldering station (http://www.jbctools.com/nast-nano-re...tegory-11.html) and I can tell you it makes it easy to piggybank a dreamcast bios! It's overkill for hobbyist stuff though, I just use it because I can, would never buy.

Picture for reference:

[TriMesh]

Yeah, I'm lucky enough to have free access to a badass soldering station (http://www.jbctools.com/nast-nano-re...tegory-11.html) and I can tell you it makes it easy to piggybank a dreamcast bios! It's overkill for hobbyist stuff though, I just use it because I can, would never buy.

Picture for reference:

Any particular reason you soldered the WE/ wire to the pin on the TSOP rather than the via? That just seems to be making life harder for yourself...

[-=FamilyGuy=-]

Any particular reason you soldered the WE/ wire to the pin on the TSOP rather than the via? That just seems to be making life harder for yourself...

I had a hard time making the solder stick to the via (you can see I tried on the pic), and using the very-fine "hook-shaped" tip and a binocular I had no issue soldering on the chip, so it saved me hassle in the end.

[bennydiamond]

Yeah, I'm lucky enough to have free access to a badass soldering station (http://www.jbctools.com/nast-nano-re...tegory-11.html) and I can tell you it makes it easy to piggybank a dreamcast bios! It's overkill for hobbyist stuff though, I just use it because I can, would never buy.

Picture for reference:

Cool stuff. I must admit that it would make it really easier to solder really small pitched devices. For the rest, I still have good, young eyes!

[OzOnE]

OK, after seeing Cybdyn's great progress with this, I thought I might paste the Verilog source for my GD EMU attempt again...
http://www.multiupload.nl/SGFLL06D53

Hopefully this will help somebody out, as I don't really have time to continue with this project atm.
The code is still at the non-booting stage ofc, but it loads up the very first part of Crazy Taxi (the black screen with the white debug text) then gives the AICA_DRV error.

The code is the one with SD card and SRAM (not SDRAM, 'cos it sucks to get working).
The SD card code is the one that came with the cheap FPGA board I was using, it's not the best and I had to modify it slightly so I can pause the transfer.

(To be honest, it's been many months since I last looked at this, and I can't remember exactly what state the code was at.)

A lot of stuff like the TOC is hard-coded, and there will be many issues and bugs to sort out.
It will also need the pin assignments changing for your specific board ofc.

Just to reiterate - this code is NOT booting game images yet!

If anyone wants to try diving in with the FPGA stuff, please don't hesitate to PM me or post on here and I'll try to answer any questions if I have time.

Good luck with the build Cybdyn! It's looking great so far.

What it really needs to test my code is a high-speed debug output via USB (which your board should be capable of?)
You could then compare between the exact data that's being transferred from the real drive / disk with the data from the Emu board.

I don't think the actual data is corrupting, so it's likely a problem with the drive status / control stuff.

Or, could just be the security data isn't correct (taken from the NullDC source).
Although, without that security data, it doesn't even attempt to boot to the license screen.

OzOnE.

[TriMesh]

OK, after seeing Cybdyn's great progress with this, I thought I might paste the Verilog source for my GD EMU attempt again...
http://www.multiupload.nl/SGFLL06D53

Thanks - this is very interesting to look at - I have actually connected one of my DCs to an FPGA, but all I've done so far is a bit of data logging, and this should encourage me to have another look at it.

(not SDRAM, 'cos it sucks to get working).

Yeah, I had a lot of fun with SDRAM and those Cyclone FPGAs - my eventual conclusion was that if you tried to connect the SDRAM clock line to the same source as the FPGA clock then it's simply impossible to meet the setup and hold time requirements. To get it working, I had to introduce about 80 degrees of negative timing skew on the SDCLK line using one of the PLLs.

[cybdyn]

i'm working on debugging of psio, so i dont know when i reach to dcio. maybe soon
i think using of ARM based controllers will help reduce time of developing and most of them have built-in hardware : SD card, sdram, usb host! controllers

[RetroJunkie]

Ah there's no rush, we've all waited this long. A little bit more will not hurt.
Plus the PSIO project is just as great a cause as DCIO! Your work is appreciated on everything!

[Bad_Ad84]

I dont like the flood technique. Once you get the knack, drag soldering you learn how much is "enough" and hardly have any excess. What excess you do what, you can "swipe" away from the pins and job done.