I tried to prototype the "reset using RTS" thing on a breadboard, but I got
troubles (as expected...). I followed the schematic and connected D2, R2, R3
and Q1 onto the breadboard.

It's as though it's acting the reverse: when I plug the serial module, it
keeps resetting the PIC.

When I plug the serial module:
  - Vrts ~ 4.1V (5V without hardware D2, R2, ...)
  - PIC doesn't blink the LED (keeps resetting)

For my tests, I used python serial module:

   import serial
   ser = serial.Serial(port="/dev/ttyUSB0",baudrate=115200)


by default, when the serial connection is created by this command, RTS = 1,
and Vrts ~ 0V. The PICs starts !

   ser.setRTS(1)  -- will reset the PIC, Vrts ~ 4.1V
   ser.setRTS(0)  -- will start the PIC, Vrts ~ 0V


So, it seems to work but on the contrary expected behavior. I would expect
that by default the PIC starts.

Does it seem weird to you too ? Or did I miss something ?


Cheers,
Seb

>
> >
> > > Also ask by Seb is the reset option by RTS (J7).
> >
> > OK this is where I'm lost... I have few questions about this:
> >
> >   - RTS and CTS in serial connector are connected to RD5 and RD4. Why ?
>
>
> If you want handshake you can use RD5 and RD4, if you don’t need
> handshake you
> Can use RD4 and RD5 on connected I/O4
>
>
> >   - when I want to reset the board using RTS, I need to switch RTS J7
> > trigger to position 1-2, as in the schematic. Is that right ?
>
> Yes, if you put it in position 2-3 you can’t use reset but you can use
> handshake.
> If I did not use the switch (is jumper) than you could not use RD4 as
> normal I/O
> because PIC would reset as soon as RD4 becomes high.
>
>
> >   - All the serial modules I've used or built have their RTS connected to
> > CTS. No flow control, quite common I think. Like in this article:
> http://www.lynxmotion.com/images/html/build125.htm. Now imagine I use such
> > a module with RTS and CTS connected. I plug it to the board. Will this
> work
> > ? Or should RTS and CTS remain unconnected from each other ? In that
> case,
> > do I have to deal with flow control ? (hope not...)
>
> Yes this will work and No you don’t need flow control, but like in
> your link don’t connect the RTS end CTS from the serial module to the
> serial connector of the Main Board else you can’t use RD4 and RD5 for
> other purpose.
>
>

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