Samsung S3C9228/P9228, 8-Bit CMOS Microcontroller user manual Timer 1 Control Register Tacon

TIMER 1 S3C9228/P9228

Timer 1 Control Register (TACON)

You use the timer 1 control register, TACON, to

—Enable the timer 1 operating (interval timer)

—Select the timer 1 input clock frequency

—Clear the timer 1 counter, TACNT and TBCNT

—Enable the timer 1 interrupt

TACON is located in page 0, at address BBH, and is read/write addressable using register addressing mode.

A reset clears TACON to "00H". This sets timer 1 to disable interval timer mode, selects an input clock frequency of fxx/512, and disables timer 1 interrupt. You can clear the timer 1 counter at any time during normal operation by writing a "1" to TACON.3.

To enable the timer 1 interrupt, you must write TACON.7, TACON.2, and TACON.1 to "1".

To generate the exact time interval, you should write TACON.3 and INTPND2.0, which cleared counter and interrupt pending bit. To detect an interrupt pending condition when T1INT is disabled, the application program polls pending bit, INTPND.2.0. When a "1" is detected, a timer 1 interrupt is pending. When the T1INT sub- routine has been serviced, the pending condition must be cleared by software by writing a "0" to the timer 1 interrupt pending bit, INTPND2.0.

Timer A Control Register (TACON)

BBH, R/W

MSB		.7	.6	.5	.4	.3	.2		.1	.0	LSB
One 16-bit timer or Two 8-bit timers										Not used
mode:
0 = Two 8-bit timers mode (Timer A/B)								Timer 1/A interrupt enable bit:
1 = One 16-bit timer mode (Timer 1)
								0 = Disable interrupt
								1 = Enable interrupt
Timer 1/A clock selection bits:
000	= fxx/512
							Timer 1/A counter enable bit:
001	= fxx/256
							0 = Disable counting operation
010	= fxx/64
							1 = Enable counting operation
011	= fxx/8
100 = fxx
101	= fxt (sub clock)					Timer 1/A counter clear bit:
110	= T1CLK (external clock)
						0 = No affect
111	= Not available
						1 = Clear the timer 1/A counter (when write)

Figure 11-1. Timer 1 Control Register (TACON)

11-2