[time-nuts] TruePosition GPS Receiver

Ben Hall kd5byb at gmail.com
Tue May 9 20:03:57 EDT 2017


Evening all,

Got brave and decided to experiment...and answered my own question below...

On 5/9/2017 6:02 PM, Ben Hall wrote:
> Does this mean that pins 7 and 8 are a TTL serial RX/TX pair that 
> function the same as J2...but without going thru the Sipex TTL-to-RS232 
> converter?  That would be a score for those of us who want to use these 
> things with Arduinos.

And the answer is sort of.

What I didn't understand in the original message is that "pins 7 and 8 
are 3.3V TTL level" meant that pins 7 and 8 are connected together.

So...

Pin 7 and 8 are connected together...and are TTL serial out.
Pin 3 and 4 are connected together...and are TTL serial in.

My little TTL-to-serial adapter is wired RX to pin 7, ground to pin 5, 
TX to pin 3.

There is a catch!  If you've got the jumper on J2 from using a real 
RS-232 port...the TTL serial input won't accept commands.  You've got to 
remove the jumper.

This makes me happy - those of us who want to use Arduinos now don't 
need to mess with going TTL to RS232 serial...can go direct TTL to TTL.

thanks much,
ben


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