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Sil3112 flashing (SATA)
- Thread starter MacJunky
- Start date
damn....
anyway, measured the voltage, and it's deffinatley 5v.
Edit, looking at the card, the traces from the flash chip seem to run straight to the sil chip, so it could just be as simple as the 5v varient of the chip will still work fine when the data lines are run at 3.3, and the solution for the PC cards would be to just use the 3.3v chip and put a regulator on the vcc pin of the flash chip
anyway, measured the voltage, and it's deffinatley 5v.
Edit, looking at the card, the traces from the flash chip seem to run straight to the sil chip, so it could just be as simple as the 5v varient of the chip will still work fine when the data lines are run at 3.3, and the solution for the PC cards would be to just use the 3.3v chip and put a regulator on the vcc pin of the flash chip
Uh oh. This may be a bigger stumbling block then. I can't find any 5V chips with equivalent chip IDs. Too weird! I wonder why they set it up to use a 5V chip. I wonder if the data and address pins are level shifted or just directly connected to the Sil3112 chip at 5V anyway. The pins might be 5V tolerant, but I don't know how good of an idea it is to only supply the flash chip pins with 3.3V when they're expecting 5V, especially when the chip is being programmed.
I would check to see if the flash chip's data and address pins go directly to pins on the Sil3112 (they do on my 3.3V card) or if they go through level shifting first. If they all go directly to the Sil3112 chip, it *might* be possible to hack your card to feed the flash chip a 3.3V supply instead of 5V by cutting traces and running wire. If they go through level shifting, it's probably still possible but a huge pain.
Firmware modification is starting to sound easier than all that though, lol...maybe if someone who's really experienced with Open Firmware stuff wants to do it, they might be able to patch the firmware. I suppose you could patch the kext and load it manually after startup, but that wouldn't make any attached drives bootable I think.
Edit: Oh, you're one step ahead of me! Yeah, if that's the case, the easiest thing to do would be to hack the card so that 3.3V goes into any pins that previously were hooked to 5V.
I would check to see if the flash chip's data and address pins go directly to pins on the Sil3112 (they do on my 3.3V card) or if they go through level shifting first. If they all go directly to the Sil3112 chip, it *might* be possible to hack your card to feed the flash chip a 3.3V supply instead of 5V by cutting traces and running wire. If they go through level shifting, it's probably still possible but a huge pain.
Firmware modification is starting to sound easier than all that though, lol...maybe if someone who's really experienced with Open Firmware stuff wants to do it, they might be able to patch the firmware. I suppose you could patch the kext and load it manually after startup, but that wouldn't make any attached drives bootable I think.
Edit: Oh, you're one step ahead of me! Yeah, if that's the case, the easiest thing to do would be to hack the card so that 3.3V goes into any pins that previously were hooked to 5V.
Good call! I would also check to make sure there aren't any other pins that are also hooked directly to 5V. Also if you hack the card, I would recommend doing it in a way such that the bypass capacitor near the 5V pin is now connected to 3.3V as well, that way you still get the benefits of that capacitor. If that's not possible I'd add another bypass capacitor for the new 3.3V supply near the chip's VCC pin.
Yep, seems there is no funny business going on between the flash chip and the sil chip, and there is a nice 3.3v regulator right below the flash chip for me to pull 3.3v from, just gotta track the 5v trace to a sutible point so i can switch it to 3.3v
found a ebay seller in france with the chips, still a little steep at £6 but not too bad for a one off buy, and it shouldn't take too long to get here
found a ebay seller in france with the chips, still a little steep at £6 but not too bad for a one off buy, and it shouldn't take too long to get here
well if yours are the same as mine there is a 3v3 regulator right under the flash chip which is the perfect place to pull 3v3 for the chip, let me know how it goes with the card 
still waiting for the damn flash chip, if it's not here tomorrow i think i'm gonna file a ebay case for a refund, can't see why it's taking so damn long...
still waiting for the damn flash chip, if it's not here tomorrow i think i'm gonna file a ebay case for a refund, can't see why it's taking so damn long...
Yep, I think it's the exact same one because there is a 3.3V regulator below the chip on mine too. Although I haven't completely verified that all the pins go directly to the Sil3112, it looks like they do and you said the same, so I'll probably just hack a board and try it out.
I do have to admit, R25 and R24 look suspiciously like supply voltage selection pads for the flash chip...I'm going to investigate them further. I'm wondering if maybe R25 populated with a 0-ohm resistor (as it is now) gives 5V, and R24 might give 3.3V. I'm going to trace it out later when I have some time, and I might be completely full of it, but it's an interesting thought anyway...
I do have to admit, R25 and R24 look suspiciously like supply voltage selection pads for the flash chip...I'm going to investigate them further. I'm wondering if maybe R25 populated with a 0-ohm resistor (as it is now) gives 5V, and R24 might give 3.3V. I'm going to trace it out later when I have some time, and I might be completely full of it, but it's an interesting thought anyway...
Yeah, I'm pretty sure that's what it's for. I can see the trace on the board (depicted in blue below) and verify it with my multimeter. It goes to R24, R25, the decoupling cap, and the the VCC pin of the flash chip. I don't know for sure if that's ALL it goes to, but it seems very likely. Here's a diagram I made of what's going on in that section of the board:
R25 supplies 5V and R24 supplies 3.3V. So you populate one of those two with a 0-ohm resistor (or a solder blob), leave the other unpopulated, and that brings the desired voltage to the flash chip. So for 3.3V flash compatibility I'm pretty sure all you have to do is move the 0 ohm resistor over to the 3.3V side (R24) instead of the 5V side (R25). I won't know for sure until I remove the 0 ohm resistor to make sure that completely isolates it from 5V, but that has to be what it's for.
R25 supplies 5V and R24 supplies 3.3V. So you populate one of those two with a 0-ohm resistor (or a solder blob), leave the other unpopulated, and that brings the desired voltage to the flash chip. So for 3.3V flash compatibility I'm pretty sure all you have to do is move the 0 ohm resistor over to the 3.3V side (R24) instead of the 5V side (R25). I won't know for sure until I remove the 0 ohm resistor to make sure that completely isolates it from 5V, but that has to be what it's for.
All right, here are my results (it works!).
I reconfigured the board for 3.3V flash instead of 5V by moving the 0 ohm resistor as described above (well, actually, I lost the resistor so I just used a solder blob). That *has* to be the purpose of those. After removing the resistor, the flash VCC pin was no longer connected to any supply voltage. So yes, at least my board can be configured for a 5V or 3.3V flash chip through those.
I changed out the included AM29F010 chip with an MX29LV040, and checked with the DOS flasher, it was definitely recognized and looks like all address pins are hooked up correctly. The chip I used already had the ROMFILE.1S2 contents flashed to it from my previous experiments. So I stuck it in my G3 Blue and White and it was recognized just like the original SeriTek card is recognized -- good sign!
Finally I shut down, hooked up a SATA drive (contains some Linux partitions) and booted the Mac again. It gave me a warning about the disk not being recognized (obviously, because Macs can't mount Linux partitions). I went into Disk Utility and sure enough, the disk was there! So I installed MacFUSE and fuse-ext2 for Linux disk support, rebooted, and the disk showed up and I can browse the contents! I haven't tested booting from it, but reading from the drive appears to work just fine.
So yes, the cheapo Sil3112 cards (well, the ones I have anyway) are compatible as long as they use a supported flash chip and you make sure they are configured to give 3.3V to the flash chip. Preliminary results look good anyway!
I reconfigured the board for 3.3V flash instead of 5V by moving the 0 ohm resistor as described above (well, actually, I lost the resistor so I just used a solder blob). That *has* to be the purpose of those. After removing the resistor, the flash VCC pin was no longer connected to any supply voltage. So yes, at least my board can be configured for a 5V or 3.3V flash chip through those.
I changed out the included AM29F010 chip with an MX29LV040, and checked with the DOS flasher, it was definitely recognized and looks like all address pins are hooked up correctly. The chip I used already had the ROMFILE.1S2 contents flashed to it from my previous experiments. So I stuck it in my G3 Blue and White and it was recognized just like the original SeriTek card is recognized -- good sign!
Finally I shut down, hooked up a SATA drive (contains some Linux partitions) and booted the Mac again. It gave me a warning about the disk not being recognized (obviously, because Macs can't mount Linux partitions). I went into Disk Utility and sure enough, the disk was there! So I installed MacFUSE and fuse-ext2 for Linux disk support, rebooted, and the disk showed up and I can browse the contents! I haven't tested booting from it, but reading from the drive appears to work just fine.
So yes, the cheapo Sil3112 cards (well, the ones I have anyway) are compatible as long as they use a supported flash chip and you make sure they are configured to give 3.3V to the flash chip. Preliminary results look good anyway!
Thanks max1zzz! And good luck getting your cards working! If you have the same card it should be a piece of cake. The hardest part was getting the old flash chip off. I hate removing PLCCs, and I hate using Chip-Quik. So I cut the leads off of two of the four sides, and then just heated up the other two sides with my iron alternating back and forth until the chip slid off. I bet a hot air station would make it a lot easier
Sadly, I don't think there's enough room to add a PLCC socket...
Sadly, I don't think there's enough room to add a PLCC socket...
Yeah I use hot air, and it's a piece of cake, 260C for 30 seconds and it just slides off the only thing with hot air is you have to be a little carefull of the caps, one of the 47uf cans on my card is looking a little battered, gonna replace that once I get my new flash chip.
the only thing with hot air is you have to be a little carefull of the caps, one of the 47uf cans on my card is looking a little battered, gonna replace that once I get my new flash chip.Nice! I definitely need to get one of those hot air things. And yes, those electrolytic caps are located in annoying places. I may have melted some of them a little bit. I just converted three more cards, and I figured I'd show off the result with all three of them plugged in:
