On Fri, 28 Feb 2014, Didier Juges wrote:
> Be careful that some GPS modules output 5V TTL. That will fry rour TS-xxxx
> in a hurry. I know that for a fact.
Or vice-versa - the true RS232 outputs from the TS7200 will fry the GPS
interface :-(. I don't think the TTL inputs like negative voltages applied!
The TS7200 outputs voltage in the RS232 voltage ranges - I believe, if
memory serves, it was a fair while ago, the output voltage levels are -5v
and +5v. There is also the problem that rs232 levels are "inverted"
compared with TTL levels.
You do need some form level conversion. The TS7200 input will need
RS232 input voltages - so you HAVE to have something to generate the
negative voltage. There are fairly simple transistor/capacitor/resistor
solutions see...
http://picprojects.org.uk/projects/simpleSIO/ssio.htm
http://www.uchobby.com/index.php/2007/06/11/ttl-to-rs232-adaptor-explained/
I've made them and they usually work ok. But using a max3232/max232 is
more guaranteed.
> You do not need RS-232 level shifters, but you may need one to go from 5V
> to 3.3V. Usually, a 4.7k resistor in series with the Tx output of the GPS
> is all you need. The input of the TS-xxxx will clamp at 3.3V and the
> resistor will limit the current to a safe value. No need to do anything
> with the Tx output of the TS-xxxx. The 5V device will accept 3.3V inputs
> just fine.
What you say pertains to interfaces 3.3v systems to 5v systems.
Interfaces either 3.3v or 5v TTL systems to true rs232 is a completely
different thing.
Jim
>
> Didier
>
>
> On Fri, Feb 28, 2014 at 9:46 AM, Jonathan Leslie <>wrote:
>
> >
> >
> > I dont' know the ts7200 specifically, but the ts7500 you just solder onto
> > the RX and GND pins to the gps modules TX and GND pins and you are hardware
> > ready to go. The GPS module broadcasts 1 a second a dump at 4800 BPS.
> >
> >
> >
> >
> >
> >
> > ------------------------------
> > *From:* Yan Seiner <>
> > *To:*
> > *Sent:* Friday, February 28, 2014 10:40 AM
> > *Subject:* [ts-7000] TTL serial on a TS7200
> >
> >
> > I have a TS7200 that I'd like to interface with a GPS module. Most of
> > the bare modules are TTL - 3.3 to 5V. Is there a way to set up a serial
> > port on the 7200 with ttl levels?
> >
> > I need RX, TX, and DCD pins active on the serial port for the GPS.
> >
> >
> >
> >
>
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