Charting

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Haz
LCD Geek
Posts: 38
Joined: Wed Jun 28, 2017 8:52 am

Charting

Post by Haz »

Hi,
I have a design I am working on, and will be using the Chart object, with 1 to 3 lines on it.
I have not decided to use the bar graph or lie on some.

The reason for my post is to find out if there is a good example for the host side on how to interface with the chart object?
I have 2 chart objects on two different screens:
1. I am charting speed, HP and Torque. I get speed from a GPS and HP and Torque from OBDII.
2. I am charting x,y Cartesian coordinates from Latitude and Longitude from GPS. So I can plot a path like the GoPro does. Starting at 0,0. This matters as you will see my question below.

I am running the LCDs with 115200baud UART. I can manage the refresh rate but I have a few questions:

1. Can I update the data points in a timer. Meaning every 500ms, trigger and send 3 sets of data point to plot.
2. Is there a way to download the graph to the host? I don't want to write anything to the SD card, it is fragile as it is (I have gone through a few during my GUI development for random reasons. Every time GTT designer crashes, I need a new SD card, but different topic).
3. What does the Auto update checkbox do? Does it refresh the chart or does it also track the min and max and auto update?
4. For chart 1, I have the min and max setup to the car min, max, and I only need to update the x-axis as we go over in time. Is this automatically done or do I need to keep track of data sets and increase max and decrease min via the host?
5. For the path chart, is there a way to have the 0 be at the center? Meaning also have the x-axis have negative numbers? Stating at 0,0, if you go in one direction, you would go negative. Can I plot negative numbers? Or do I need to normalize on the host again and only plot positive x numbers? I would want to adjust min and max for both x and y axis as I drive. Or better yet, remove all axis and just have the data points.
Like the attached.
GPSCapture.PNG
GPSCapture.PNG (221.23 KiB) Viewed 221 times
Any help before I start going at it and learning the hard way would help. These 2 screens are the last of 12 I have on the 7in screen. Never used chart objects, so trying to scope the work before I start coding.
Thanks,
H-

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