where can i find wm8850 uart pins?

[kez...@gmail.com]

title

[Alexey Charkov]

I'm afraid there's no general answer to this one, as it's completely
board specific. I usually just poke with my TTL-USB Rx wire to
promising-looking pads on the board while having the GND wire
connected to some USB port shielding, while rebooting the board and
watching the terminal for any coherent text.

Port settings are most often 115200 8n1. There are usually not that
many pads with two parallel PCB traces going straight to the SoC (as
should be the case for a UART port), so it doesn't take too long to
find the right one.

Best,
Alexey

On Thu, Feb 27, 2025 at 6:12 PM kez...@gmail.com <kez...@gmail.com> wrote:
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[kez...@gmail.com]

I have bricked my netbook, i think i found those Pins but output is Blank. I just wanted to reflash my uboot via uart

[Alexey Charkov]

You need some sort of bootloader running for that. If you don’t get any UART output at all, it likely means that your W-Load is corrupt, meaning you can only revive the device by reflashing its SPI chip in an external programmer (or maybe JTAG).

Unlike, say, Rockchip devices, WM8850 doesn’t have any built-in alternative to its primary bootloader, so if it gets damaged you are out of options. It’s best not to mess with the bootloader image at all here.

Best,

Alexey

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