GPS bolt on demo code to read GPS data and broadcast over CAN bus

[brentpicasso]

Read the GPS NMEA string that contains GPS data it arrives from the GPS module

Use arduino string parsing routines and this guide (there are other guides) to extract the data.

https://w3.cs.jmu.edu/bernstdh/web/common/help/nmea-sentences.php

Data values we want to extract:

• Latitude
• Longitude
• Speed (Ground Speed)
• GPS quality indicator

Broadcast the following over CAN bus with the following format

Broadcast the following information:

CAN ID 100

• Latitude in signed decimal degrees. 4 byte payload (Multiply value by 1000000 to get 6 digits of precision, pack into 4 bytes)
• CAN byte offset 0-3

===========

• Longitude in signed decimal degrees. 4 byte payload (Multiply value by 1000000 to get 6 digits of precision, pack into 4 bytes)
• CAN byte offset 4-7

Can ID 101

• Speed in signed decimal degrees. 2 byte payload (Multiply value by 100 to get 2 digits of precision, pack into two bytes)

• CAN byte offset 0-1

• GPS quality indicator. 1 byte payload (value is typically 0,1,2)

• Can byte offset 2

[brentpicasso]

More details:

• broadcast on CAN1
• use the ping pong demo as a starting point - remove the "receive" code and only have the broadcast code on CAN1.
• broadcast per the specifications listed in this issue