On 5/7/20 10:52 AM, Stewart C. Russell via talk wrote:
On my desktop (i7-4790K, 32 GB DDR3, Asus H97M-E) I've run out of serial ports I can usefully access via USB serial adapters*. The motherboard does have a real COM port on it, though, and just after I built the system I added an adapter cable/bracket (one of these, IIRC: https://www.canadacomputers.com/product_info.php?cPath=5_1336_1449&item_id=094057). But it's never worked as a port, and I want to make it work.
It's enabled in the BIOS and Linux (Ubuntu 19.10) finds it:
ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
I'm a member of `dialout`, and the ports seem to check out:
$ ls -l /dev/ttyS0 /dev/ttyUSB0 crw-rw---- 1 root dialout 4, 64 May 6 21:54 /dev/ttyS0 crw-rw----+ 1 root dialout 188, 0 May 3 07:50 /dev/ttyUSB0
No data goes in or out. Curiously `stty -F /dev/ttyS0` hangs for a few seconds, but that's the only odd thing I see.
Hardware serial ports are kind of ancient history. Anyone remember ancient magic to make 'em work? There's a chance that ASUS don't use the standard serial pin header assignment: I'll trace that if necessary. The headers and cables tended to be pretty standard. Usually the headers have a pin missing and the plug would have a hole filled but if not it would be easy to put the cable on backwards.
you should make sure you have hardware flow control disabled. There are a number of programs for managing serial ports but I have had reasonably good luck with minicom. -- Alvin Starr || land: (647)478-6285 Netvel Inc. || Cell: (416)806-0133 alvin@netvel.net ||