Dorothy Luai

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9 years, 10 months ago.

Could not connect to the network.

Hi Sir, I have tried the main.cpp of Seed_GRPS_Shield. I could not connect to the network.

The way i connect is: p9(TX) of mbed to D0(RX) of Seeed Studio GPRS Shield V2.0 and p10(RX) of mbed to D1(TX) of Seeed Studio GPRS Shield V2.0.

VU of(5.0v USB Out) Mbed to VIN of GPRS Shield, and GND to GND.

I used Starhub MaxMobile Prepaid Card. (https://www.starhub.com/business/support/internet-ip-solutions/faqs/prepaid-mobile-broadband.html)

I print out in putty terminal and it printed as follow:

Could not connect to network. Retrying!

May I know what would be the problems?

Thank you so much:D

Regards Dorothy

Question relating to:

Last updated: 06 May 2014
a library to use GPRS like ethernet or wifi, which makes it possible to connect to the internet with your GPRS module

main.cpp that I used:

  1. include "mbed.h"
  2. include "GPRSInterface.h"

/ On many platforms USBTX/USBRX overlap with serial on D1/D0 pins and enabling the below will interrupt the communication.

  • You can use an LCD display to print the values or store them on an SD card etc.
  • / Serial pc(USBTX, USBRX);

/**

  • D1 - TX pin (RX on the WiFi side)
  • D0 - RX pin (TX on the WiFi side)
  • 115200 - Baud rate
  • "apn" - APN name
  • "username" - APN username
  • "password" - APN passowrd
  • / GPRSInterface eth(D1, D0, 115200, "eshppd", "NULL", "NULL");

int main() {

wait(3);

Initialize the interface. If no param is passed to init() then DHCP will be used on connect() int s = eth.init(); if (s != NULL) { printf(">>> Could not initialise. Halting!\n"); exit(0); }

printf(">>> Get IP address...\n"); while (1) { s = eth.connect(); Connect to network

if (s == false || s < 0) { printf(">>> Could not connect to network. Retrying!\n"); wait(3); } else { break; } } printf(">>> Got IP address: %s\n", eth.getIPAddress());

Prepare the http request to mbed.org char http_cmd[] = "GET /media/uploads/mbed_official/hello.txt HTTP/1.0\n\n"; TCPSocketConnection sock; sock.connect("mbed.org", 80); sock.send_all(http_cmd, sizeof(http_cmd)-1); printf(">>> Sent request to mbed.org\n");

Read the response char buffer[300]; int ret; while (true) { ret = sock.receive(buffer, sizeof(buffer)-1); if (ret <= 0) break; buffer[ret] = '\0'; printf(">>> Received %d chars from mbed.org:\n%s\n", ret, buffer); } sock.close();

Disconnect from network eth.disconnect(); return 0; }

posted by Dorothy Luai 12 Jun 2014

your main.cpp seems not correct, please refer to https://mbed.org/users/lawliet/code/Seeed_GPRS_Library_HelloWorld/file/46f9e36be3fa/main.cpp ,thanks

posted by wei zou 12 Jun 2014

1 Answer

wei zou
9 years, 10 months ago.

hello, can you show me your main.cpp?

Accepted Answer

Hi I used your main.cpp. Thank you so much for your superfast reply.

Here is the main.cpp that I used:

  1. include "mbed.h"
  2. include "GPRSInterface.h"

/ On many platforms USBTX/USBRX overlap with serial on D1/D0 pins and enabling the below will interrupt the communication.

  • You can use an LCD display to print the values or store them on an SD card etc.
  • / Serial pc(USBTX, USBRX);

/**

  • D1 - TX pin (RX on the WiFi side)
  • D0 - RX pin (TX on the WiFi side)
  • 115200 - Baud rate
  • "apn" - APN name
  • "username" - APN username
  • "password" - APN passowrd
  • / GPRSInterface eth(D1, D0, 115200, "eshppd", "NULL", "NULL");

int main() { wait(3);

Initialize the interface.

If no param is passed to init() then DHCP will be used on connect()

int s = eth.init();

if (s != NULL) {

printf(">>> Could not initialise. Halting!\n");

exit(0);

}

printf(">>> Get IP address...\n");

while (1) {

s = eth.connect(); Connect to network

if (s == false || s < 0) {

printf(">>> Could not connect to network. Retrying!\n");

wait(3);

} else {

break;

}

}

printf(">>> Got IP address: %s\n", eth.getIPAddress());

Prepare the http request to mbed.org

char http_cmd[] = "GET /media/uploads/mbed_official/hello.txt HTTP/1.0\n\n";

TCPSocketConnection sock;

sock.connect("mbed.org", 80);

sock.send_all(http_cmd, sizeof(http_cmd)-1);

printf(">>> Sent request to mbed.org\n");

Read the response

char buffer[300];

int ret;

while (true) {

ret = sock.receive(buffer, sizeof(buffer)-1);

if (ret <= 0)

break;

buffer[ret] = '\0';

printf(">>> Received %d chars from mbed.org:\n%s\n", ret, buffer);

}

sock.close();

Disconnect from network

eth.disconnect();

return 0;

}

APN that I used is MaxMobile Prepaid Card APN.

I found this APN from this website:

https://www.starhub.com/business/support/internet-ip-solutions/faqs/prepaid-mobile-broadband.html

posted by Dorothy Luai 12 Jun 2014

I am from Ngee Ann Polytechnic. I am currrently doing my final year project. I would appreciate it very much.

Thank you so much Sir. Looking forward to your reply. :D

Regards

Dorothy

posted by Dorothy Luai 12 Jun 2014