Re: BeagleBone Black doesn't boot without serial console (10.0 release)

[Jason Thorpe <thorpej%me.com@localhost>]

> On Oct 11, 2024, at 6:36 AM, Mouse <mouse%Rodents-Montreal.ORG@localhost> wrote:
> 
>> From the schematic here:
>> https://github.com/beagleboard/BeagleBone-Black/blob/master/BBB_SCH.pdf
>> there is a pulldown resitor on UART0_RX input.
> 
> You call it a pulldown, not a pullup, so I infer it's pulling the pin
> to a more-negative voltage level.
> 
> In RS-232, the more negative level is marking, in which case that is
> not a problem; that's the correct way to pull it.  But since you say

The UART pins on all of these small single-board ARM computers are logic-level signals, not RS232.  To use them with RS232, you’ll need to add an RS232 charge pump.

-- thorpej