Kontron KTAM3874-pITX - Manual (Page 62)

KTD-S0057-I Page 58 Linux® Programming Examples (DebianTM)
KTAM3874/pITX Software Guide
/* Set PWM mode */
write_timer_reg (TCLR, (read_timer_reg (TCLR) &
~(TCLR_GPOCFG | TCLR_PT | TCLR_TRG | TCLR_SCPWM)) |
(TCLR_PT | TCLR_TRGOVFLMAT));
return 0;
}
int start_pwm (unsigned long duty_cycle)
{
unsigned
long val;
/* Check the duty cycle value */
if ((duty_cycle < 0) || (duty_cycle > DUTY_MAX))
return -1;
/* Set the reload value */
write_timer_reg (TCLR, read_timer_reg (TCLR) | TCLR_AR);
write_timer_reg (TLDR, RELOAD_VAL);
write_timer_reg (TTGR, 0);
/* Set the match value */
write_timer_reg (TCLR, read_timer_reg (TCLR) | TCLR_CE);
val = (FREQ_VAL * duty_cycle) / DUTY_MAX;
write_timer_reg (TMAR, RELOAD_VAL + val);
/* Write the counter value */
write_timer_reg (TCRR, -1);
/* Start the timer */
if (! (read_timer_reg (TCLR) & TCLR_ST))
write_timer_reg (TCLR, read_timer_reg (TCLR) | TCLR_ST);
return 0;
}
int stop_pwm (void)
{
int
i;
if (read_timer_reg (TCLR) & TCLR_ST)
{
/* Stop the timer */
write_timer_reg (TCLR, read_timer_reg (TCLR) & ~TCLR_ST);
/* Check if timer off */
for (i = 0; i < STOP_TIMEOUT; i++)
if (! (read_timer_reg (TCLR) & TCLR_ST)) break;
if (i >= STOP_TIMEOUT)
return -1;
}
return 0;
}