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Peter-Easton / android-debug-cable-howto

This is a simple how-to to create your own android kernel debugging cable using commercially available parts.
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Pixel 3 console TX not worked #7

Closed pingwuu closed 3 years ago

pingwuu commented 3 years ago

Hi, I build my adapter for pixel 3, now minicom console can output phone's kernel log, but I can not input anything。 Anything I missed? thanks.

My adapter connection as below, and my USB2TTL signal is 1.8V: USB2TTL GND <---> TypeC Adapter's A1. USB2TTL RXD <---> TypeC Adapter's A8 USB2TTL TXD <---> TypeC Adapter's B8

pingwuu commented 3 years ago

For uart tx worked, Need change any kernel configure or bootcmd parameter? Thanks.

samueldr commented 3 years ago

Hi,

my USB2TTL signal is 1.8V

Good thing you gave this information. While the TTL logic level is not specified in the main text, it links to a 3.3V TTL Serial Cable.

This makes me believe that you're able to get TX because 3.3V, while overwhelming the 1.8V adapter, is fine. Though RX might not work because while it's trying real hard, there is not 1.8V is not enough.

In my instance, my serial adapter is using a 3.3V TTL adapter too. I would hazard a guess the same for others who followed the guide.

With that said. There is a lot of advice online stating 1.8V should be used with phones. That they will be damaged otherwise. It is unclear to me, at this point, whether this holds true for the Pixel type-c serial cable or not.

pingwuu commented 3 years ago

Hi @samueldr ,

Thanks for your reply. I changed TTL logic level to 3.3v, it seems Phone's RX is not worked. Maybe I need change another type-c adapter and try again.

pingwuu commented 3 years ago

Using build kernel, both TX and RX worked. Maybe factory has some security option for console RX enable.