They are not, either. The “black PCB version” you bought have a fatal flaw never addressed for years, or decades. Search for “ch341a 3.3v fix”. This programmer can’t change the voltage of the data lines. When programming 3.3v chips, it can supply 3.3v on power line, but 5V on data line.
It’s probably okay to use a few times, I never heard any BIOS chip fryed because of this. Pushing over the spec limit is not a good idea.
There are “green PCB version” which fixes the issue by adding a voltage switch jumper. However there quickly occurred “black PCB version” reprinted in green…
The general suggestion is measure the voltage yourself and fix if need.
Or… not buying a SPI programmer! I bought a nice “USB to parallel port adapter”, with blue PCB, and there are jumpers to set voltage and SPI mode. The only hurdle is that you need to wire up the sop clip, because the pinout is way different from a bios chip.
It also doesn’t have the programming socket, which is useful if you are not using sop clips.
They are based on the same IC, CH341a. CH341a isn’t just a programmer IC. It supports all kinds of protocols including parallel port and SPI.
He’s point is that there’s not much amps on data lines. Well, think again, these chips are logical chip, they are not designed to sink much amps either.
I didn’t find the max output current. but check the conditions when output voltage was measured, only 100uA. That’s the current the chip is supposed to work. Input is usually in high impedance mode, so no current is expected at all. If the high voltage causes some insulation breakdown, then a mA will be way over spec and can do some real damage.
“How can you fry something with just a milliamp?” You sure can. He’s basically assuming anything “burned out” must be overheating and molten inside. Not really, there can be an electrical breakdown with no apparent sign. Think about how static electricity damages a chip. It could kill the I/O driver circuit of the data pin, and nothing else.
The chips nowadays are made at such minuscule scale, that they can only process a few uA. If you pump mA into it, it can break. Unlikely, but possible.
It’s fine to use a few times, so many people used it, no repored incidents. (Or at least nobody reports because the motherboard wasn’t really working to begin with) I’d rather not taking the risk.
After all, the parallel port adapter is much cheaper than the programmer. If the cheaper one can recognize and bother to fix the issue, why not the more expensive one? A jumper doesn’t even cost a cent. And there is 3.3v rail on board, already. The only thing needed is to switch the input voltage of ch341a.
This is not workmanship, and by no way “good quality”.
I did read about that but I didn’t apply the fix because I read that it doesn’t really matter. Also, I wasn’t sure if still applies to newly sold programmers. I will try to measure and apply the fix before I next use it.
Thoughts on the video:
It is reassuring that it takes him 4-5 times to place the clip because I have never gotten it right the first time.
Since placing the clip is hard, it doesn’t really matter that Vcc is 3.2V and data lines are 4.8V because you will inevitably attach Vcc to a data line and attach the data line to Vcc just because placing the clip is hard and it can’t be done right the first time every time. However, the currents being low is reassuring.
As to the quality of the programmer, the 3.3V vs 5V issue aside, imo a 3.3V line should be 3.3 - 3.4V and not 3.2V and 5V line should be 5V-5.1V and not 4.8V, so that’s bad too.
Going back to my original issue. As I wrote, there is a second server of the same build/model. That server never received a wrong BIOS. In fact, after the screw up with the first server, I made sure, that every BIOS was explicitly for “S1200v3RPS” . Now, on this server the BMC stopped working too after a complete unplugging of the server’s power cord.
That doesn’t really make any sense to me because on the second server, I never did anything wrong as far as I know.
I updated 03.01.0002 to latest by also updating to every version in between because some versions have a minimum version they can be upgraded from.
So I went from 03.01.0002 → 03.02.0002 → 03.03.0003, updating everything each time (BIOS, ME, BMC) using startup.nsh and doing a reset each time as per instructions. After each update, everything worked, until now I pulled the plug and the BMC stopped working.
Regarding CH341- what do you expect for this price? This is a rather cheap tool which does quite a lot for the money. And it solves some tasks more expensive tools don’t comlete because of much more advanced control mechanisms.
The voltage on the data lines is a affected by many factors, that voltage might run up to the Vcc of the chip when floating/ not connected.
