[Country EMBED strategy] [062] [Touch screen working principle analysis]

Touch-screen Initialization

1. Set the ad conversion clock

Adccon (1<<14) |   (49<<6) Prscen Enable PRSCVL adc=pclk/(val+1)

2. Set Interrupt Masking

2.1.TC interrupts, which can occur when a finger touches or moves away

2.2.ADC interrupt, interrupt generated when ADC conversion is complete

Enable TC Interrupt, shielded ADC interrupt, poll to see ADC interrupt

Intmsk ~ (1<<31)

Intsubmask ~ (1<<9)

3. Enter the wait interrupt mode (press)

ADCTSC 0xd3

TC Interrupt Handling

1. Start XY coordinate auto-conversion

ADCTSC (1<<2)

Adccon (1<<0)

2. Wait for the conversion to complete, get the coordinates

Judge Adccon's 15-bit

Get the x-coordinate in ADCDAT0

Get the y-coordinate in ADCDAT1

3. Clear interrupts

SUBSRCPND's 9-bit

SRCPND's 31-bit

INTPND's 31-bit

4. Enter standby interrupt mode (bounce)

ADCTSC 0xd3

ADCTSC 8th bit set to 1

5. Clear interrupts

6. Enter the wait interrupt mode (press)

[Country EMBED strategy] [062] [Touch screen working principle analysis]