Bachelor of Applied Technology
ETEC: 6416 Microcontrollers
Laboratory 2: GPS in Hi-tech C
Task: set up a project using MPLab and undertake USART communication with a GPS unit.
Pay attention to the way the code ‘looks’ are all the brackets lined up? Do you have a header?
Are the comments easy to follow and do they make sense?
Introduction
There are a number of implementations for extracting GPS data from a GPS using a
microcontroller however when using a different microcontroller the code needs to be ported
from the original microcontroller to the target microcontroller. Performing the port requires
knowledge of the structure of how the original code works and knowledge of the changes that
need to be made to the special function registers in order to get the code to run on the target
MCU. Additionally the code will not always work first time as expected so debugging skills
using a USART are required. For the laboratory, using the echo program as a base shell
(secure code that can read a USART signal and send a USART signal to a terminal) undertake
a port of some GPS code to a PIC16f877a MCU and have the longitudinal and latitudinal data
displayed on the terminal. The GPS data will come from a GPS log file (a simulated GPS
data set).
-some of the code is taken from the Hi-Tech C samples and requires specific Special Function
Registers to be set for the PIC16f877a running a 20MHz oscillator. The challenge of this
laboratory is to correct the special function registers to provide the correct communication
speeds for the PIC16f877a and a GPS operating at 9600baud.
1. Open MPLAB>project>project wizard.
2. Save the project to a folder on your desktop called ‘proj2’ that you can later move to
your student directory.
3. Port the code from the handout on to a PIC16f877a MCU.
4. Correct the Special function register settings to provide a 9600 SPI communication
using xxxx. Test the code using the MPLab simulator.
5. Run a test communicating with a microcontrollers using one of the GPS log files to
obtain GPS latitude/longitude data and display the GPS data on the terminal package.
The file to port across is adapted from the website
http://tutorial.cytron.com.my/2012/08/16/skm53-gps-module-starter-kit-skgps-53/
In this code the port must replace the LCD display with a display using the Terminal
Package (terminal or realterm). Structurally the code would be better if the goto
command system used by the original code was replaced by functions (goto is
unreliable in C and can cause the microcontroller to perform an exception).
This laboratory is a major undertaking and will comprise 6% of your final mark.
Submission guidelines, submit your .c files and .h and a word document containing
screen print of the code working (as demonstrated by the terminal program). Deposit
all files in the moodle laboratory 2 dropbox
F:\ETEC 6417-Embedded Software\tutorials
Page 1
Lab Supervisor Comments
Signature of Lab Supervisor on completion of laboratory exercise
F:\ETEC 6417-Embedded Software\tutorials
Page 2