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  • Author Author: Jan Cumps
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C++ library for ST Teseo GPS - pt. 5: ready for a first (0.1) firmware release

Jan Cumps

The Teseo-LIV3 GPS module (as used in  ' GPS / Galileo / BeiDou / GLONASS receiver) talks UART and I2C. I'm writing an OO driver for it, for embedded systems. The firmware is now ready for a release.

GitHub Release 0.1, with binaries.

image
image: actual output of the firmware for Pico

Functionality:

  • Talks to ST Teseo-LIV3 GPS in query-response mode.
    you send a query, and get the reply
  • UART and I2C supported.
    same functionality with both protocols.
  • predefined functionality for NMEA commands $GPGLL, $GLGSV, $GPRMC.
    low level write, read, and parse functions can be used for the other NMEA commands
  • reply validation.
    for the predefined functions, the library validates the NMEA status line
  • supports commands that return single and multiline lines of data.
    single line commands fill a string with the response.
    multiline commands fill a vector of strings with all response lines. The library reports the count of lines.
  • initialisation option.
    you can pre-program the Teseo to work in reply-response mode (persistent).
    but if you want to keep the factory settings, the library can configure the Teseo (nonpersistent)
  • platform independent.
    will work on any platform, that supports UART or I2C
    you provide the reader and writer for the protocol, and (optionally) a reset function.
    current firmware example tests the lib with a Raspberry Pico 

Pico connections for I2C, UART and shared functions

A connection deep dive in available in this post:  C++ library for ST Teseo GPS - pt. 4: PCB to Pico hardware connections . The instructions will work for different Teseo boards. I used the board that shabaz published on the e14 community:  Fun With Arduino, Global Navigation Satellite Systems (GNSS) and Teseo III .

Pico resources used only if you use I2C:

  • I2C0
  • SDA: GP16 (Pico I2C0 SDA)
  • SCL:  GP17 (Pico I2C0 SCL)
  • baud: 100 * 1000

for I2C, SDA connects to SDA and SCL to SCL. The PCB that I use has the pull-ups for I2C.

Pico resources used only if you use UART:

  • UART1
  • TX: GP4 (Pico UART1 RX)
  • RX:  GP5 (Pico UART1 Tx)
  • baud: 9600
  • UART1 RX interrupt

for UART, RX connects to TX and vice versa

Pico common resources:

  • RESET: GP18 (optional)
  • 5V: VBUS
  • 0V: GND

image
image: how to hook up the Teseo PCB to a Pico.

The binary firmware file (.uf2) - built for I2C -  can be downloaded from GitHub.

Next post:  C++ library for ST Teseo GPS - pt. 6: running library built-in requests, and free conversations 

visit the github repository (git clone https://github.com/jancumps/pico_gps_teseo.git)
view the online documentation
Link to all posts.

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