Gameduino sensor input delay

[desiredshoe]

Hello everyone, I'm looking to make an automotive display for my car and happen to stumble across gameduino and the ftdi chipset.  I had a decent prototype with a Nextion display but the quality left a lot to be desired.   I'm running an hotmcu display, FT811CB-HY50HD with an Arduino Mega as the MCU.  

I have the display up and running and the code is working how it should but I'm having an issue with sensor input delay.  There seems to be a .5 second delay from changing the input to when the screen refreshes.  I'm monitoring the serial data and that seems to be updating instantly.  Since this display will be using in an automotive environment with fast acting sensors, I would like the display to react pretty quick to some inputs.  Below is a video showing the delay I'm talking about. 

I've tried playing with the SPI speed but it's still the same.  If anyone knows a fix, I would greatly appreciate it.




photos.google.com/share/AF1QipOg--8Wr3xfvGXt-kRSg_UdWM7wer5DUSCgEqYqKPp0sksBLEzAOFgmvwIVACOsvw?key=bmxPX2xELWJOWUs4NVoxVFluanJTQjhzNjItOVJ3

[desiredshoe]

Here's my code...


#include <SPI.h>
#include <GD3.h>

#define PDPin 8

int analogPIN = 0;
int val = 0;
int KPA = 0;

void setup()
{
 
 Serial.begin(9600);
 
 pinMode(PDPin, OUTPUT);
 digitalWrite(PDPin, HIGH);  
 delay(20);
 digitalWrite(PDPin, LOW);
 delay(20);
 digitalWrite(PDPin, HIGH);
 delay(20);

 delay(500);
 GD.begin(3);

 for (int i = 0; i <= 0; i++) {
 GD.wr(REG_PWM_DUTY, i);
 delay(100);
}
}

void loop()
{
 GD.ClearColorRGB(0x000000);
 GD.Clear();
 GD.cmd_text(600, GD.h / 2, 31, OPT_CENTER, "KPA");

 GD.ColorRGB(0x229954);
 GD.cmd_gauge(200,200,220,12544,9,5,(KPA*1.23),250);

 GD.ColorRGB(0x000000);
 GD.PointSize(16 * 150);
 GD.Begin(POINTS);
 GD.Vertex2ii(200,200);

 GD.ColorRGB(0xFF0000);
 GD.cmd_gauge(200,200,200,12544,9,5,KPA,100);
 GD.ClearColorRGB(255,255,255);

 GD.ColorRGB(0xFFFFFF);
 GD.cmd_number(200,300,31,OPT_RIGHTX,(KPA));
 
 GD.ColorRGB(0xFF0000);
 GD.cmd_gauge(600,147,112,12544, 5,5,KPA,250);
 
 GD.cmd_bgcolor(0x000000);
 GD.cmd_progress(20,450,600,20,OPT_FLAT,KPA,250);


 GD.swap();
 
 val = analogRead(analogPIN);
 KPA = map(val, 0, 1023, 0, 100);
 Serial.println(KPA);
 
}

[jamesbowman]

Yes, the GPU has a graphics work FIFO, which is full all the time and it's holding about 30 frames of data. That's why it's drawing aboout .5 seconds in the past.

To fix this call:

GD.finish();
just before you do the analog sensing.

GD.finish() returns after all drawing has actually reached the display. It's similar to OpenGL's glFinish().

[desiredshoe]

Thanks! Works perfectly now!

Now begins the fun part of designing the gauge layout.