Receiving raw hex or binary from serial port in Linux shell

[mrkenneth]

I am working with some AXIS network cameras (namely the AXIS 221 and the AXIS 2420). The cameras contain a web server using an ETRAX 100(LX) CRIS processor running ELinux. I can use Telnet to access the shell (mish) as root.

I would like to interface a Dallas Semiconductor 1-Wire temperature sensor (most likely the DS18B20) via the serial port. I am using the DS9097U-009 RS-232 to 1-Wire adapter as the interface between the camera and the temperature sensor. The adapter contains a DS2480B serial 1-Wire line driver.

I am able to successfully transfer commands to the 1-Wire adapter using:
[tt] echo -n "\[three-digit octal number]" >/dev/ttyS1[/tt]

Incidentally, the following does not output the intended hexadecimal number:
[tt] echo -n "\x[two digit hexadecimal number]" >/dev/ttyS1[/tt]
It outputs [tt]\xFF[/tt]. But I have already converted all of the required 1-Wire commands to octal.

The temperature sensor outputs a 16-bit code through the 1-Wire adapter to represent the temperature. However, I cannot seem to find a way to receive the raw 16-bit number. I am currently using the following command to receive the data:
[tt] dd if=/dev/ttyS1 bs=1 count=2[/tt]

The input is converted into ASCII before being displayed or saved. How can I receive the 16-bit number that I can later convert to a decimal number?

Thank you in advance!

P.S. I have not had much experience with Linux. Most of my programming has been for Microchip PIC microcontrollers.

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[richs]

Hiya-
Turn off the canatonical processing of the incoming serial
data stream and use the read function to read the 4 bytes
of data. Optionally, you might have to read the carriage
return and line feed (so the read will be 6 characters in
length, not four). Then it is a simple procedure to
convert the binary to hex, octal, or whatever.

You might want to point your browser to:

http://ou800doc.caldera.com/en/SDK_sysprog/_TTY_in_Raw_Mode.html

and/or

http://www.win.tue.nl/~aeb/linux/lk/lk-11.html

and, although I haven't looked at it in detail you might
also like:

http://www.cs.unc.edu/~taylorr/musicbox/src/termio.C

Hope that these help!


Cheers,

Rich S.