* Re: Testing the serial port of TQM823L
2000-08-16 21:32 ` Testing the serial port of TQM823L Prashant Patel
@ 2000-08-16 23:49 ` Wolfgang Denk
0 siblings, 0 replies; 3+ messages in thread
From: Wolfgang Denk @ 2000-08-16 23:49 UTC (permalink / raw)
To: Prashant Patel; +Cc: linuxppc-embedded
Hi,
in message <008501c007c9$81ecbad0$fd2f7ece@kennedy> you wrote:
>
> I am working with TQM823L board. It has two serial ports. I am using
I guess that's my bailiwick, then ;-)
> one serial port RS-232-2 ( and device ttyS0) to run the kernel stored in
> flash. Once the kernel is running, i think i can access another serial port
> RS-232-1 through device ttyS1. I have one program which writes on device
Right. You have configured SMC2 for serial console, and want to use
SMC1 as additional serial port.
> ttyS1. When i run that program, it is supposed to turn on the motor attached
> to serial port RS-232-1(i.e device ttyS1). But it didn't work. When i
> tested my program with other board, it works fine.
Use a simpler setup for testing; attach another termial (any computer
with a free serial port running some terminal emulation) to the TQ
board.
The use "echo some text >/dev/ttyS1" to send some characters to the
serial port; you should see the characters "some text" on the
connected terminal. The type "cat /dev/ttyS1" on the console, and
type "some other text" on the connected terminal. You should see the
characters "some other text" on the console.
If this doesn't work it makes no sense to try any fancy programs you
might have.
> When i use "setserial" command, i got following message.
> >setserial -ga /dev/ttyS0
> >Cannot get serial info. : invalid argument.
> >setserial -ga /dev/ttyS1
> >Cannot get serial info. : invalid argument
"setserial" is not supported (and not necessary) on MPC8xx systems.
> so i don't know where i am making mistake. How could i test whether
> serial port RS-232-1 is receiving data, whenever i write to device ttyS1?
> And How could i test whether serial port RS-232-1 is live or not, after
> running kernel through serial port RS-232-2 (device ttyS0).
There are a few important issues:
* Make sure you are using the latest version of kernel sources; for
the TQM8xxL see either
ftp://ftp.denx.de/pub/LinuxPPC/usr/src/linux-2.2.13-2000-08-01.tar.bz2
or
ftp://ftp.denx.de/pub/LinuxPPC/usr/src/linux-2.4-2000-08-01.tar.bz2
* Keep in mind that TQ has a very special pin-out on the connector
for SMC1, (mis-) using some modem handshake signals for other
purposes. If you don't have full control over those lines you
better play io safe and use a cable with 3 wires only (GND, RxD,
TxD).
* Make sure your receiving side does not wait for hardware handshake
signals. I'm using a cable like this with my TQ systems (assuming a
standard 9 pin serial connector):
3 wires (GND, RxD and TxD) connect the TQ board to the other
system, and on the "other system" side there are local connections of
DTR with DSR and RTS with CTS resp.
TQ board other system
RxD 2 ------------------------- 3 TxD
TxD 3 ------------------------- 2 RxD
GND 5 ------------------------- 5 GND
CD 1 n.c. n.c. 1 CD
DTR 4 n.c. +- 4 DTR
DSR 6 n.c. +- 6 DSR
RTS 7 n.c. +--- 7 RTS
CTS 8 n.c. +--- 8 CTS
RI 9 n.c. n.c. 9 RI
Let me know if you have any other problems.
Wolfgang
--
Software Engineering: Embedded and Realtime Systems, Embedded Linux
Phone: (+49)-8142-4596-87 Fax: (+49)-8142-4596-88 Email: wd@denx.de
Another megabytes the dust.
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