Author: christop
Posted: 30 Oct 2012 11:52:56 pm (GMT -5)
My CA-42 cable came in! (Actually it arrived yesterday but my wife didn't tell me until late last night, so...)
I plugged it in and apparently it is a Prolific 2303, just like a real CA-42 cable. I tried shorting the RX and TX lines but got a bunch of garbage coming back in the terminal. Turns out that gpsd was sending data to it (curse you, ESR!!) which it promptly sent back to my terminal. After wrestling with gpsd for far too long, I tried it again and got a clean echo! Not bad for $2.27!
Here's the pinout for future reference (for myself or anyone else):
6 white RX 3.5V
7 green TX 0V (not pulled up)
8 blue GND
(Wire colors may vary.)
Nothing else was connected. I have not yet cracked open the USB case to see what signals are available directly from the circuit board (of course, I don't need any other signals for talking to a calculator). That's a project for another day. I started on this little project too late tonight as it is. Another project is to make a simple voltage divider to connect it to a TI link port (unless this cable can tolerate 5V+ coming from the link port).
Anyway, it's bedtime for me.![Smile]()
_________________
Christopher Williams
Posted: 30 Oct 2012 11:52:56 pm (GMT -5)
My CA-42 cable came in! (Actually it arrived yesterday but my wife didn't tell me until late last night, so...)
I plugged it in and apparently it is a Prolific 2303, just like a real CA-42 cable. I tried shorting the RX and TX lines but got a bunch of garbage coming back in the terminal. Turns out that gpsd was sending data to it (curse you, ESR!!) which it promptly sent back to my terminal. After wrestling with gpsd for far too long, I tried it again and got a clean echo! Not bad for $2.27!
Here's the pinout for future reference (for myself or anyone else):
6 white RX 3.5V
7 green TX 0V (not pulled up)
8 blue GND
(Wire colors may vary.)
Nothing else was connected. I have not yet cracked open the USB case to see what signals are available directly from the circuit board (of course, I don't need any other signals for talking to a calculator). That's a project for another day. I started on this little project too late tonight as it is. Another project is to make a simple voltage divider to connect it to a TI link port (unless this cable can tolerate 5V+ coming from the link port).
Anyway, it's bedtime for me.
_________________
Christopher Williams