Martin Bochud

Important changes to forums and questions

All forums and questions are now archived. To start a new conversation or read the latest updates go to forums.mbed.com.

10 years ago.

fopen doesn't work with UbloxUSBModem library on C027?

Hi, I'm using the C027 board with a sdcard connected on P1_20-21-23-24. When I'm trying to use the fopen function my program stops. I did the following tests : - If I remove the fopen function, my program works good but without access to the sdcard. - If I keep the FATFileSystem and remove the UbloxUSBModem library, my program work good and it can access to the sdcard.

Any idea ?

Thanks in advance

Question relating to:

Last updated: 27 Aug 2020
The u-blox-C027 is a complete starter kit that allows quick prototyping of a variety of applications for the Internet of Things. The application board has a MAX-M8Q GPS/GNSS receiver and …

1 Answer

Michael Ammann
10 years ago.

The memory is very limited on the LPC1768 and the mbed_official modem driver are very demanding (RAM/FLASH/CPU). Maybe you are running out of memory? You can also try to use the updated C027_Support library which also contains a simple driver that exposes the modem api. There is a sample application called C027_SupportTest to give you a start.

Import libraryC027_Support

support library for C027 helper functions for Buffer Pipes, Buffered Serial Port (rtos capable) and GPS parsing. It includes modem APIs for USSD, SMS and Sockets.

Last commit 20 Apr 2017 by u-blox

Import programC027_SupportTest

C027_Support library test

Last commit 11 Aug 2016 by u-blox

Thank you for your answer Michael. The idea of my application is to read every hour 6 data on a RS232 device (connected on UART3), to send them to a website (thingspeak) and at the same time the data are saved on a SDcard. The bin file is about 50ko. I've base my program on the C027_HTTPClientTest because I need doing a POST on a http address. First I had problems with the compatibility between serial port and RTOS and I solve that using the advices of Tyler Weaver ( http://mbed.org/users/tylerjw/notebook/buffered-serial-with-rtos/) and that works very good. Afterward I've added the HTTPClient.lib and UbloxUSBModem.lib from the C027_HTTPClientTest (I use the same fatfilesystem lib. and the mbed_rtos lib. used in the UbloxUSBModem library). With the C027_HTTPClient libraries, I can compile the program but when I reset the C027, it freezes shortly after. and as I said before, when I removed them, everything works. I tried to modify the FATFileSystem lib. based on a post made by Tyler Weaver here http://mbed.org/forum/mbed/topic/3980/ but I did it without understanting what I was doing and that doesn't work. What can I do ?

posted by Martin Bochud 11 Apr 2014