On Tue, Oct 24, 2023 at 5:52 AM Crystal Kolipe <kolip...@exoticsilicon.com> wrote:
> On Mon, Oct 23, 2023 at 11:37:10PM -0400, Morgan Aldridge wrote: > > I have experimented with the following with no change in the underlying > > issue of the terminal showing the login prompt, but each character input > > causing the login prompt to be resent: > > If you short the tx/rx lines at the DE-9 end and then access the serial > device using /usr/bin/cu on the OpenBSD machine, does your input > reliably each back to you? Or are some characters lost or garbled? > > (Obviously remove or disable the ttys line for this test.) > Excellent suggestions! I have since found the pinouts for the serial cable and successfully confirmed the wiring, no shorts to ground or other pins, and no odd resistance on any of the connections. That's a good start. On the terminal, keeping the same 9600 8N1 settings, but enabling local echo, and shorting the TX/RX pins gets me duplicated input with no odd characters or breaks (AFAICT). On the OpenBSD side (with getty disabled on the tty, of course), I ran `cu dr -l ttyU1 -s 9600` and jumped the TX/RX pins, and confirmed that the characters entered were received back without any breaks or odd characters (though there's no local echo.) I confirmed that cu(1) is just not echoing locally by un-jumping the TX/RX pins and seeing that I did _not_ receive the characters entered. > You might need to short rts/cts and dtr/dsr as well depending on your > hardware handshaking setup. > I _think_ I have not enabled hardware handshaking, but will test this next. Also, having just typed this out, I realize I forgot to test using cuaU1 with cu(1), in addition to ttyU1. Morgan
