Epson RX-8564LC n, bit, bit, bit, bit, bit, bit, bit, bit, AIE, TIE, TD1, TD0, TD1, Data, 1 Hz, 1 < n, W / R, 64 Hz, TI / TP, TI / TP, 4096 Hz, 122 ∝ s, 244 ∝ s, 1/60 Hz

RX − 8564 LC

13.2.2. Related registers for function of timer interrupts.

Address [h]	Function	bit 7	bit 6	bit 5	bit 4	bit 3	bit 2	bit 1	bit 0
01	Control 2	0	⋅	0	TI / TP	AF	TF	AIE	TIE
0E	Timer control	TE	⋅	⋅	⋅	⋅	⋅	TD1	TD0
0F	Timer	128	64	32	16	8	4	2	1

∗Before starting the fixed-cycle timer interrupt function each time, be sure to write a value (preset value/Reg-0F[h]) as the timer's down counter value (when TE = "0").

(Note) Note with caution that the preset value must be set or reset to enable correct operation.

∗Before entering operation settings, we recommend first clearing the TE bit to "0" and then clearing the TF and TIE bits to "0" in that order, so that all control-related bits are zero-cleared (= set to operation stop mode) to prevent hardware interrupts from occurring inadvertently while entering settings.

1)TI / TP bit ( Interrupt Signal Output Mode Select. Interrupt / Periodic )

When a fixed-cycle timer interrupt event occurs, this bit selects whether to end the operation after one iteration or to repeat the operation.

TI / TP	Data	Description
	0	[Level interrupt mode]
		Fixed-cycle timer interrupt function operates one time only (∗ )
Write / Read		∗ ) Another operation can be set via various bit settings.
	1	[Repeated interrupt mode]
		Fixed-cycle timer interrupt function operates repeatedly

2) TD1, TD0 bits ( Timer countDown interval select 1, 0 )

These bits specify the fixed-cycle timer interrupt function's countdown period (source clock). Four different periods can be selected via combinations of these two bit values.

						/INT auto recovery time tRTN
TD1, TD0	TD1		TD0		Source clock	during repeated interrupt mode
	( bit 1 )		( bit 0 )			Preset value	Preset value
						n = 1	1 < n
	0	0		4096 Hz	/ 244.14 ∝ s cycle	122 ∝ s	244 ∝ s
W / R	0		1	64 Hz	/ 15.625 ms cycle	7.813 ms	15.625 ms
	1	0		1 Hz	/ Updated per second	15.625 ms	15.625 ms
	1	1		1/60 Hz	/ Updated per minute	15.625 ms	15.625 ms

∗1) During repeated interrupt mode (TI/TP bit = "1"), the auto recovery time tRTN (when the /INT pin is switched from low level to Hi-Z) varies according to the source clock and preset value, as shown above.

∗2) The countdown when a 1-Hz source clock has been selected is linked to updating of the internal clock's seconds setting.

∗Since the internal clock is linked to updating of the seconds setting, if the timer is started at a clock time of 0.9 seconds, the first countdown will occur only 0.1 second later. (The second and subsequent countdowns will occur at the correct time interval.)

∗2) The countdown when a 1/60-Hz source clock has been selected is linked to updating of the internal clock's minutes setting.

∗Since the internal clock is linked to updating of the minutes setting, if the timer is started at a clock time of 50 seconds, the first countdown will occur only 10 seconds later. (The second and subsequent countdowns will occur at the correct time interval.)

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