/*
 * FreeCalypso buzzer "melodies" have times measured in TDMA frames,
 * as that is the time unit in the main firmware which will ultimately
 * play them.  In this standalone buzzer player we simulate TDMA frame
 * timing by programming Calypso TIMER1 with the period of 1875, and
 * we detect timer overflow (one virtual TDMA frame time having passed)
 * by polling the read register to avoid the need for interrupt handling
 * infrastructure.
 */

#include "types.h"
#include "timer.h"

void
timer_init()
{
	TIMER1_REGS.cntl = CNTL_CLOCK_ENABLE;
	TIMER1_REGS.load = 1875;
	TIMER1_REGS.cntl = CNTL_CLOCK_ENABLE | CNTL_AUTO_RELOAD | CNTL_START;
}

void
wait_for_tdma_frame()
{
	u16 read1, read2;

	read1 = TIMER1_REGS.read;
	for (;;) {
		read2 = TIMER1_REGS.read;
		if (read2 > read1)
			return;
		read1 = read2;
	}
}