Texas Instruments MSP430 User Manual

406
const struct Element down_element =
{
.inputPxselRegister = (unsigned char *)&P2SEL,
.inputPxsel2Register = (unsigned char *)&P2SEL2,
.inputBits = BIT3,
// When using an abstracted function to measure the element
// the 100*(maxResponse - threshold) < 0xFFFF
// ie maxResponse - threshold < 655
.maxResponse = (100 + 655),
.threshold = 100
};
//*** CAP TOUCH HANDLER *******************************************************/
// This defines the grouping of sensors, the method to measure change in
// capacitance, and the function of the group
const struct Sensor multi_buttons =
{
.halDefinition = RO_PINOSC_TA0_WDTp,
.numElements = 3,
.baseOffset = 0,
// Pointer to elements
.arrayPtr[0] = &up_element, // point to up element
.arrayPtr[1] = &down_element, // point to down element
.arrayPtr[2] = &middle_element, // point to middle element
// Timer Information
.measGateSource= GATE_WDT_ACLK, // 0->SMCLK, 1-> ACLK
.accumulationCycles= WDTp_GATE_64 //64 - Default
};
Similarly, the sensor structure is also modified for these three elements.
The main code is almost identical to the single sensor demo. However, the variable keyPressed is used
to check which element was touched. According to touch on different element states of Launchpad
board LEDs are altered.
keyPressed = (struct Element *)TI_CAPT_Buttons(&multi_buttons);
if(keyPressed)
{
// Up Element
if(keyPressed == &up_element)
{
P1OUT |= BIT0;
}
// Down Element
if(keyPressed == &down_element)
{
P1OUT |= BIT6;
}
// Middle Element
if(keyPressed == &middle_element)
{
P1OUT = 0;
}
}

Texas Instruments MSP430 Specifications

General

Brand	Texas Instruments
Model	MSP430
Category	Microcontrollers
Language	English