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#include <stdint.h>
#include <stdlib.h>
#include <chopstx.h>
#include <mcu/mkl27z.h>
struct TPM {
volatile uint32_t SC;
volatile uint32_t CNT;
volatile uint32_t MOD;
volatile uint32_t C0SC;
volatile uint32_t C0V;
volatile uint32_t C1SC;
volatile uint32_t C1V;
uint32_t rsvd0[13];
volatile uint32_t STATUS;
uint32_t rsvd1[7];
volatile uint32_t POL;
uint32_t rsvd2[4];
volatile uint32_t CONF;
};
static struct TPM *const TPM1 = (struct TPM *)0x40039000;
static chopstx_intr_t tpm1_intr;
#define INTR_REQ_TPM1 18
uint16_t
touch_get (void)
{
/* Assert LOW. */
PORTB->PCR1 = (1<<8) /* GPIO */
| (0<<6) /* DriveStrengthEnable=0 */
| (0<<4) /* PassiveFilterEnable=0 */
| (1<<2) /* SlewRateEnable = slow */
| (0<<1) /* pull enable = 0 */
| (0<<0) /* puddselect= 0 */
;
/*
* Start the timer's counter.
* TOF clear, TOIE=1, CPWMS=0, CMOD=1, PS=011.
*/
TPM1->SC = 0xcb;
/* Let the register to pull it up. */
PORTB->PCR1 = (3<<8) /* TPM1_CH1 */
| (0<<6) /* DriveStrengthEnable=0 */
| (0<<4) /* PassiveFilterEnable=0 */
| (1<<2) /* SlewRateEnable = slow */
| (0<<1) /* pull enable = 0 */
| (0<<0) /* puddselect= 0 */
;
chopstx_intr_wait (&tpm1_intr);
/* Clear overflow and CH1 capture. */
TPM1->STATUS = 0x102;
/* Stop the counter. */
TPM1->SC = 0;
return TPM1->C1V;
}
void
touch_init (void)
{
chopstx_claim_irq (&tpm1_intr, INTR_REQ_TPM1);
/* Input capture mode: MSB = 0, MSA = 0 */
/* Rising edge: ELSB=0 ELSA=1 */
TPM1->C1SC = 0x84;
TPM1->POL=0;
/* No trigger. */
/* Stop on overflow: CSOO=1 */
/* Run the timer in the debug mode */
TPM1->CONF = 0x000200c0;
}
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