EVK-M10 Driver

Overview

Driver for interfacing with ublox's M10 GNSS Chip through $I^2C$ on the STM32 platform.

Implemented Features

Currently the driver is capable of reading the M10's stream buffer through I2C Fast Mode and parsing the received data in the NMEA format, automatically handling message slicing and loosing stream buffer sync.

Important

The driver is meant to be used with the NMEA message specification, and not UBX.

Currently the following NMEA messages have implemented parser functions:

1. RMC (Recommended Minium Data): According to ublox's interface description, section 2.7.17.1, the RMC message has the mos essential data for a GNSS system, such as, but not limited to: Latitude, Longitude, Speed Over Ground.

On how to implement new parser functions, please check this project's wiki, which goes deeper into implementation detail and driver architecture.

How to Use

Setup

STM32

To setup this system on the STM32 platform:

1. Put the nmea_parser.c, nmea_parser.h, m10gnss_driver.c, and m10gnss_driver.h files in your project's Src directory.
2. Enable the I2C peripheral (in FAST MODE).

uBlox EVK

It is also necessary to setup a couple of configurations on the EVK's side. To do so, you need to download uBlox's uCenter 2 software.

After that, you need to setup:

• I2C output
• NMEA as the output format
• The RMC message rate of output

All this configurations need to be sent to the module after all power down.

The easies way is to use the i2c_stm_com.ucf config file, which already has all the configurations listed, so just load the file into uCenter2 and press send.

Example Use

This directory has an example in the application.c file under the evk_m101_driver/Core/Src file, but in short:

#include "m10gnss_driver.h"
#include "application.h"
#include "gpio.h"
#include "i2c.h"

m10_gnss gnss_module = {
                            .i2c_address = I2C_ADDRESS,  // The address of the ublox module
                            .i2c_handle = &hi2c1         // Handler for configured I2C peripheral
                        };


void ApplicationMain(void){

    // Initializes the driver by clearing the ublox module's stream buffer
    M10GnssDriverInit(&gnss_module);
    while (1)
    {
        // Read the buffer and parse the RMC messages
        M10GnssDriverReadData();

        // If the latitude is available from the last reading, toggle the onboard LED
        if(gnss_module.latitude.is_available)
            HAL_GPIO_TogglePin(LED_GREEN_GPIO_Port, LED_GREEN_Pin);

        HAL_Delay(100);
    }
    
}

Porting to Another Platform

Since the whole parsing logic and conversion from NMEA string message to numerical values is all platform agnostic, it may be of interest to port this code to another platform other than an STM32 micro-controller.

To do that, you only need to:

• Change the void M10GnssDriverReadStreamBuffer(void) function, which is the one responsible for making the I2C communication to the one specific to your application, in the m10_gnss_driver.c file.
• Change the m10_gnss struct, to either remove the handler to the I2C peripheral or use the one specific to you platform, in the m10_gnss_driver.h file.
• Remove the #include "i2c.h" directive from the m10_gnss_driver.h file.

Important

As state in the module's data sheet, only $I^2C$ FAST MODE is supported, so make sure your platform supports it, or use UART.