running Touch in background while doing other tasks on 40x2

[James Ward]

I am building an led cube, and am using the picaxe 40x2 to both receive touch inputs from a single touch input while pulsing the leds at the same time. does anyone know how I would do this. I am open to suggestions such as using a second small 08m2 to handle the touch simultaneously.

 

[hippy]

Welcome to the PICAXE forum.

There is no ability to run TOUCH in the background on an X2. Using a PICAXE 08M2 could be the best option. That can set an output high when touched and the 40X2 can check that as an input signal.

 

[James Ward]

Thanks so much hippy how much of a delay would an if command take to run just to check pin input high or low if i added a resonator to take it up to 64mhz? rough numbers don't matter. also toying with the idea of using an 08m2 as the "brains" and then using a slave 40x2 as an interface to the led matrix. possible?

 

[westaust55]

An IF...THEN command will take of the order of 40 microsec to perform with an X2 part operating at 64MHz (16MHz resonator).

 

[inglewoodpete]

Contrary to what hippy says, it is possible to use Touch in the background on a 40X2.

I created a "Noughts and Crosses" (Tic Tac Toe) game on a 28X2, whose silicon is almost the same as the 40X2.

I used a 100mS timer interrupt to read 9 Touchpads. A "touch" event was only validated after its "release" event was detected. The foreground task did regular averaging of the readings as well as actioning the inputs: driving 9 outputs connected to LEDs.

It was not a particularly easy thing to do. The touch inputs' sensitivities are affected by the number of outputs being driven, so the touch event had to be compared with a dynamic threshold. This threshold was calculated from the averaging of each Touch pad's idle condition. For more details of the problems with Touch, refer to this post from last year.