serial port questions

Guylhem Aznar nanonote at guylhem.net
Tue Apr 27 14:54:12 EDT 2010


Hello

Following the latest message about a potentially missing 2nd uart, I
think it's time to test and check.

First, regardinng the voltage used by the serial port, before I fry
anything I would like a confirmation :
 - is it 3.3V ie CMOS ?
 - is it 5V ie TTL?

On http://en.qi-hardware.com/wiki/Serial_console#Hardware_mod_to_have_a_pluggable_serial_port2010/4/10
I see a reference to TTL and to 3.3V (??) because of a link to the
FTDI TTL-232R-3V3 USB-to-TTL cable.

I have a  FTDI TTL-232R-5V USB-to-TTL cable in my drawer. I would like
to quickly test the 2nd uart, because it is reported after kernel
boot, and echo > devfile is not giving any error
(Morever, following the wiki, if someone else wired and used the 2nd
uart, I wonder what is the current situation)

Second, regarding the HomeRF module considered, would it be possible
to buy one to try to hook it up to a serial port, to get started
writing some software for it?

Thanks
Guylhem




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