Optional GPRS Interface

The NB1010 can optionally accommodate the GC864 GPRS module manufactured by TELIT (www.telit.com).

The GPRS module is controlled through the NB1010's serial port 4. A dedicated general-purpose I/O (GPIO) line — GPIO54 — is used for multiplexing this serial port:

• When the output buffer of GPIO54 is disabled (default post-reset state) or the line is HIGH, serial port 4 is switched to the interboard cable connector — lines TX3 (#31), RX3 (#29), RTS3 (#7), and CTS3 (#39).
• When the output buffer of GPIO54 is enabled and the line is LOW, the serial port is switched to the GPRS module. In this state, your application can communicate with the GPRS module through serial port 4 (and use flow control, too).

GPIO55 of the NB1010 is connected to the reset pin on the GPRS module. To put the module in reset, enable this line and set it HIGH. For reliable reset, keep the reset applied for at least 2 seconds. To release the module from reset, set GPIO55 LOW. Note that the GC864 module module may take up to 1 minute to boot, recognize the SIM card, and become operational.

GPIO line manipulation is performed using the io. object, while the ser. object is responsible for serial port communications.

Actual data exchange via the GPRS module are the domain of the sock. object. Before such data exchange can take place, the GPRS interface must be properly configured. This is jointly achieved by the ppp. object and the GPRS library.