00:02 <Hammdist> trying to connect to orange pi 5 uart. I think I have the pins correctly connected (gnd -> gnd, reader rx -> device tx) but what uart speed should I use with screen?

00:05 <DC-IRC> <efectn> 1500000

00:11 <Hammdist> tried that, tried some other speeds, I keep getting gibberish. oh well at least I know the pins are connected for now

00:20 <Hammdist> verified that my adapter should support 1.5mbps (it goes up to 3mbps)

00:25 <Hammdist> I get a lot of @ symbols in the gibberish

00:26 <Hammdist> that's a leading one with many zeros. maybe an indication that the speed is way too high?

00:33 <Hammdist> well i've tried 1500000 numerous times and bunch of other common speeds for uart, but nothing

00:34 <Hammdist> the nature of the gibberish changes as I change the speed though. so things are hooked up right but I'm not hitting the right speed

01:27 <Hammdist> the USB adapter I'm using is CP2102N USB to UART Bridge Controller

02:02 <archetech> 15000000

02:03 <DC-IRC> <Tonymac32> Yeah a cp2102 should handle it

02:03 <DC-IRC> <jkent.net> 15 megabaud?

02:03 <DC-IRC> <jkent.net> lol

02:04 <DC-IRC> <Tonymac32> They are expensive enough. 😑 1.5M

02:04 <DC-IRC> <Tonymac32> 1 500 000

02:04 <archetech> yup rock64 uses 1.5m

02:05 <DC-IRC> <jkent.net> Hammdist, i'd double check your ground

02:05 <DC-IRC> <Tonymac32> Si

02:19 <DC-IRC> <tenkawa42> I've had the same problem with all of my recent rk3588* uart connections

02:19 <DC-IRC> <tenkawa42> on multiple socs and multiple cables and images

02:52 <Hammdist> how do I write to the serial port from armbian? I have only ttyS9, I don't think it's the right one. how come there is no ttyS0? is this a systemd thing whereby it got reserved somehow?

02:54 <Hammdist> wait maybe it supposed to be AMA0

02:56 <Hammdist> the /proc/cmdline shows ttyS2 is expected

03:15 <Hammdist> well it isn't a speed setting problem

03:16 <Hammdist> one can send commands in and get some responses out of the serial port. like if I send "dmesg" I get a bunch of gibberish. or if I send "reboot" the board reboots. so it is hooked up to a shell and at least sending stuff works

03:17 <DC-IRC> <jkent.net> huh, interesting

03:32 <Hammdist> seems to be a character by character mapping that gets applied on the output. I can't figure out what the function is though. it's clearly not reversible however since x y and z all map to p

04:25 <Hammdist> hm. looking at the mapping a bit more, it seems to be a pattern that the decoded character always ends in a zero bit (LSB). I think this means the problem could be that the sampling is too fast and it's picking up part of the start signal as the LSB. could it be that the prescaler is wrong in hardware and it's transmitting at a slightly slower

04:25 <Hammdist> speed than intended? I don't see an easy way to change to a non-standard speed in linux ...