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Teensy++, NANDway and SEM001: boot or RLOD?
Teensy++, NANDway and SEM001: boot or RLOD? –
Since most forum information I found is probably outdated (teensy doesn't do NAND?), I figured I'd start a thread and ask for some more information. I got my SEM001 on the bench, hooked it up according to the diagrams found on the wiki, including the tristate testpad, other wires directly to the IC. Most forum posts from <2012 say NAND consoles do not have tristate, but the wiki says otherwise. To prevent interference the teensy has its own 3v3 LDO, grounds connected with 28AWG (signals 30AWG kynar), console powers NAND.
Long story short: Teensy disconnected and console boots, teensy on gives me a RLOD blinking. This is pretty confusing, because I thought the idea of the tristate is that it would hold the console in limbo, preventing the NAND to be accessed and therefor would not attempt to boot. Some posts say that you always need external power for SEM001, is this true? Then what's the tristate pin for? If there's no other way, is there a better point for supplying 3V3 to the mainboard? I could not find any and supplying 3v3 to the IC socket or the decoupling cap is ridiculous, there's got to be a better point somewhere.
With USB disconnected and console booting, the teensy led does stay on (meaning R/B of NAND1 stays high). Is this to be expected? Does RLOD kill the 3v3 supply to the NAND? When attempting to read NAND info, the first attempt takes a while (4secs approx) before I get the 0xFF read error, second attempt produces an error instantly, meaning the microcontroller could be crashed or something. I'm not too confident when it comes to the Teensy quality, because I received mine with bad soldering under the microcontroller. I fixed it myself by fluxing and reflowing in a professional oven which did the trick, but the teensy could still be at fault. That is why I'd like more up-to-date information before I start digging for the problem.
Thanks in advance
what i use with teensy is supply 3V3 externally and directly to NAND chip pins - pin12 is VCC and pin13 GND - the adjacent pins11 and 14 are not connected internally to the chip, which makes it easier to solder. i even use 2xAA 1V5 batteries as power source. so, you don't need to power-up the whole console, just the NAND chip and those 2xAA 1V5 batteries hold 4-5 full reads (writes).
Originally Posted by littlegamer
You know what? That was actually a great idea! Tried 2 tri-state testpoints soldered directly to ground which could not prevent the console getting booted, so I gave it a shot. Coincidentally I just happened to have a 2xAA batteryholder lying around from a DIY kit and it worked like a charm. I did find a better 3V3 testpoint for supplying the power using a testpoint diagram (not allowed to post the link), 3V3 point was confirmed by my multimeter. This setup gave me 3 identical dumps from both chips that passed the BwE validator for 98%. New batteries and 2 error-free verified writes. So at 20 minutes for a dump and 45 minutes for a verified write, I got 2 hours of reliable power from these babies. Plus it saved me a trip to the lab to borrow a power supply
Originally Posted by vronz