Searching for NM-B911 power sequence

[Antonynl]

I can't find the power sequence in the attached schematics and I want to investigate this board because it does not power up but the white led besides the power buttonturns on when power button gets pushed.

[mon2]

Re: Searching for NM-B911 power sequence

Review pg 96.

[Antonynl]

Re: Searching for NM-B911 power sequence

I've seen that but it doesn't provide an explicit sequence?

[mon2]

Re: Searching for NM-B911 power sequence

No but check the voltage path flow from left to right side. Check each enable pin and respective output voltage to confirm it is present and within range of the specified value.

[Antonynl]

Re: Searching for NM-B911 power sequence

for now SYSON is not generated on pin107 of the IT8227E :-/

To me it seems to be a corrupted BIOS with the IT8227E which I never programmed (yet).

[mon2]

Re: Searching for NM-B911 power sequence

Remove all power -> check the resistance to ground of pin107. If the resistance is not low then yes, it may be the firmware of the noted device.

[Antonynl]

Re: Searching for NM-B911 power sequence

81K so looks fine. I cant even see a glitch or something on the scope.

So how do I read and write the bios of this board when the IT8227E contains the bios image?

[mon2]

Re: Searching for NM-B911 power sequence

Personally do not have the experience in such parts (yet) but it is very possible that the main bios will reflash this component so it is a bit of a catch-22 if the logic board is not booting. Wait on feedback from others.

From a brief study of this and ENE parts - the parts are often 8051 based and with SPI flash interface.

[Antonynl]

Re: Searching for NM-B911 power sequence

I programmed a few Winbond 25Q chips but not these. Indeed catch22 situation: also SIO cant read an image from USB

[ktmmotocross]

Re: Searching for NM-B911 power sequence

just flash main bios

[Antonynl]

Re: Searching for NM-B911 power sequence

just flash main bios

Yes you're right the sio has its own spi memory chip.

Thanks

[Antonynl]

Re: Searching for NM-B911 power sequence

I don't get a clock on the bios chip U0901 clock pin and also not on pin 105 of the KBC IT8227E.

The strange thing is that the led near the power button goes on when the powerbtn is pushed.

Is IT8227E toasted for sure or is there another way to test IT8227E kbc?