A class for collecting information from the touch panel over I2C. More...

Public Member Functions
def	__init__ (self, x_m, x_p, y_m, y_p, width=None, length=None, origin=INTERCEPT)
	Initialize a TouchPanel driver object. More...

def	get_x (self)
	Get the x-coordinate of the current touch. More...

def	get_y (self)
	Get the y-coordinate of the current touch. More...

def	has_contact (self)
	Detect if the touch panel is currently being touched. More...

def	scan (self)
	Scan the touch panel to detect for contact (z coordinate) and x and y position. More...

Public Attributes
	x_m
	x- pin

	x_p
	x+ pin

	y_m
	y- pin

	y_p
	y+ pin

	slope
	Slopes used for linear calculation of position.

	origin
	Origin used for linear calculation of position.

Detailed Description

A class for collecting information from the touch panel over I2C.

This class can be used to get X and Y positions as well as scan for contact.

Constructor & Destructor Documentation

◆ init()

def drivers.TouchPanel.TouchPanel.__init__	(	self,
		x_m,
		x_p,
		y_m,
		y_p,
		width = `None`,
		length = `None`,
		origin = `INTERCEPT`
	)

Initialize a TouchPanel driver object.

This object expects the pins connected to +/-x and +/-y. Optionally a width, length, and origin can be specified in order use this class with a different sized touch panel than provided on the ME 405 test bench, or to tune where the exact center is. Note that the physical dimensions are always assumed to be 176mm x 100mm.

Parameters

x_m	A pyb.Pin object connected to x-. This object must be connected to an analog adc.
x_p	A pyb.Pin object connected to x+. This object must be connected to an analog adc.
y_m	A pyb.Pin object connected to y-.
y_p	A pyb.Pin object connected to y+. This object must be connected to an analog adc.
width	Optionally set the width by measuring the difference in adc counts across the touch panel.
length	Optionally set the length by measuring the difference in adc counts across the touch panel.
origin	Optionally set the geometric origin by providing an [x, y] coordinate offset (as measured in adc counts).

Member Function Documentation

◆ get_x()

def drivers.TouchPanel.TouchPanel.get_x ( self )

Get the x-coordinate of the current touch.

Sets x- pin to low, x+ pin to high, floats the y+ pin, and takes an analog measurement of the y- pin. Pins are left in this mode upon exit.

Returns: Returns the x-coordinate in mm of the current touch. If the panel is not being touched then the value returned is unspecified.

◆ get_y()

def drivers.TouchPanel.TouchPanel.get_y ( self )

Get the y-coordinate of the current touch.

Sets y- pin to low, y+ pin to high, floats the x- pin, and takes an analog measurement of the x+ pin. Pins are left in this mode upon exit.

Returns: Returns the y-coordinate in mm of the current touch. If the panel is not being touched then the value returned is unspecified.

◆ has_contact()

def drivers.TouchPanel.TouchPanel.has_contact ( self )

Detect if the touch panel is currently being touched.

Sets y- pin to high, x- pin to low, floats the y- and pin, and takes an analog measurement of the x+ pin. Pins are left in this mode upon exit. Checks to see if the measured voltage is higher than LOW_THRESHOLD.

Returns: Returns the true if the panel is being touched, otherwise false.

◆ scan()

def drivers.TouchPanel.TouchPanel.scan ( self )

Scan the touch panel to detect for contact (z coordinate) and x and y position.

Scans x, z, then y coordinates, taking advantage of pin mode settings for a faster read time than scanning each individually. If the panel is not being touched then the values for x and y position returned are meaningless. Results of timing tests using test_TouchPanel-timing.py :

method	average time (µs)
get_x	330
get_y	330
has_contact	295
scan	660

Returns: Returns a tuple of [x, y, z] where x and y are coordinates in mm and z is a boolean value dictating if the panel is currently being touched.

The documentation for this class was generated from the following file:

labFF/drivers/TouchPanel.py

Public Member Functions

Public Attributes