Thanks for the info Craig, That makes things a lot clearer. And I'll
dive into the PXA developer manual.
I switched it over to HWUART and turned it off 48-51 like you suggested
and ttyS3 is now working. I'm using the following stty and pppd commands
to link two machines via a serial null modem.
stty -F /dev/ttyS3 speed 19200 crtscts cs8 -parenb -cstopb
stty -F /dev/ttyS3 speed 19200 crtscts cs8 -parenb -cstopb
pppd crtscts debug noauth 192.168.1.129:192.168.1.182 /dev/ttyS3 19200
I have to do the stty command twice for some reason, the first time I
always run it it sets the speed to 9600, but after the second time I run
the command it always sets it fine.
and on the other end,
stty -F /dev/ttyS1 speed 19200 crtscts cs8 -parenb -cstopb
pppd crtscts debug noauth 192.168.1.182:192.168.1.129 /dev/ttyS1 19200
This creates the network connection between the two machines, which
works, however I've hooked up a resister and led to each cts/rts lines
and I see no activity. As far as I can tell I'm using the correct
commands to enable flow control.
The main reason I want to get flow control working is that if I try to
stream traffic down the line and come near the maximum connection speed
of 19200, it will stop for 1-2 seconds, every 5-10 seconds. I'm assuming
this is because there is no flow control. The same setup works fine
between two normal pc's.
-Jon
Craig Hughes wrote:
> On May 25, 2006, at 12:33 AM, Jon Keller wrote:
>
>> modprobe proc_gpio
>> echo "AF1 out" > /proc/gpio/GPIO42
>
> That would put gpio42 into an unspecified mode. AF1 in would be
> BTRXD. AF1 out is unspecified.
>
>> echo "AF1 in" > /proc/gpio/GPIO45
>
> Again, AF1 in is unspecified for GPIO45. AF2 out would be BTCTS.
>
>> If I make this change do I still use all of the BTUART pins on the
>> gpsstix? or do I move my wires to the HWUART and the cts/rts of the
>> BTUART?
>
> You can use the BTUART pins (physical lines GPIO42 through GPIO45) as
> either the BTUART or HWUART, depending on how you set the alt function
> on those lines. Refer to the PXA developer manual to find the settings:
>
> BTUART HWUART
> 42 AF1 in AF3 in
> 43 AF2 out AF3 out
> 44 AF1 in AF3 in
> 45 AF2 out AF3 out
>
>
> Whether it's BT vs HW impacts whether you use ttyS1 or ttyS3 under
> linux. It also affects slightly the semantics of how flow control is
> controlled by the hardware/software. The physical lines are the same
> though in both cases. If you use HWUART on those lines, then you
> should probably disable it from the other lines (GPIO48-GPIO51) so
> that you don't get weird echo effects or other noise issues.
>
> C
>
>
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