Good day!
I actually have a strange effect when I plug my FTDI card.
My modules:
I do have an Arduino Mini Pro 3.3V and I am working with a Macbook Air.
My GPS module is a SIM968C
Senario:
My Arduino use the pin 9,12,13 to power my GPS module.
Power process:
http://www.hello-web.net/temp/t.png
First the pin13 goes HIGHT to put hight the pin STDBYN of my GPS module. The STDBYN is pull down internaly.
40ms after, the pin 12 hoes HIEGHT and put a transistor in saturation to give 3.3V to pin GPS_VCC of my GPS module
Finally, 50ms the 9 goes HIGHT to put the pin GPS_RST hight. The GPS_RST is pull up internaly.
Arduino manager that process juste before leaving the setup loop.
AND THEN, the pin 56 of my GPS module (output), goes HIGHT and turn on a LED, called GPS_STDBYOUT.
May be, I can provide you a schema of my pins connection
STDBYOUT:
http://www.hello-web.net/temp/GPS_STDBYOUT.png
GPS Powering:
http://www.hello-web.net/temp/GPS_VCC.png
The problem with ma FTDI:
When I turn on the battery to power my board, "I can guess" that process run well, because there is the STATUS led and NETLIGHT led flashing in a good order and I also add another led which flash where the Arduino leave the setup loop. The GPS_STDBYOUT is flashing at good time.
When I plug my FDTI card from my Mac to the Arduino mini pro, the GPS_STDBYOUT is flashing immediately.
Do you have an idea why?
Above, I add some link to my schema to see how I connected my GPS module pins in order to let Atduino Mini pro to power it
If someone has a experience how to power a SIM968C module and tell me which value of transistor and resistence to use, it would be great and magic :o)
Thank for your help