Intel 8XC251SQ, 8XC251SA, 8XC251SP, 8XC251SB, Embedded Microcontroller manual Address S89H Reset State

8XC251SA, SB, SP, SQ USER’S MANUAL

TMOD	Address:	S:89H
	Reset State:	0000 0000B

Timer/Counter Mode Control Register. Contains mode select, run control select, and counter/timer select bits for controlling timer 0 and timer 1.

7

GATE1 C/T1# M11 M01

0

GATE0 C/T0# M10 M00

Bit	Bit				Function
Number	Mnemonic
7	GATE1	Timer 1 Gate:
		When GATE1 = 0, run control bit TR1 gates the input signal to the timer
		register. When GATE1 = 1 and TR1 = 1, external signal INT1 gates the
		timer input.
6	C/T1#	Timer 1 Counter/Timer Select:
		C/T1# = 0 selects timer operation: timer 1 counts the divided-down
		system clock. C/T1# = 1 selects counter operation: timer 1 counts
		negative transitions on external pin T1.
5, 4	M11, M01	Timer 1 Mode Select:
		M11 M01
		0	0	Mode 0:	8-bit timer/counter (TH1) with 5-bit prescalar (TL1)
		0	1	Mode 1:	16-bit timer/counter
		1	0	Mode 2:	8-bit auto-reload timer/counter (TL1). Reloaded
					from TH1 at overflow.
		1	1	Mode 3:	Timer 1 halted. Retains count.
3	GATE0	Timer 0 Gate:
		When GATE0 = 0, run control bit TR0 gates the input signal to the timer
		register. When GATE0 = 1 and TR0 = 1, external signal INT0 gates the
		timer input.
2	C/T0#	Timer 0 Counter/Timer Select:
		C/T0# = 0 selects timer operation: timer 0 counts the divided-down
		system clock. C/T0# = 1 selects counter operation: timer 0 counts
		negative transitions on external pin T0.
1, 0	M10, M00	Timer 0 Mode Select:
		M10 M00
		0	0	Mode 0:	8-bit timer/counter (T0) with 5-bit prescaler (TL0)
		0	1	Mode 1:	16-bit timer/counter
		1	0	Mode 2:	8-bit auto-reload timer/counter (TL0). Reloaded
					from TH0 at overflow.
		1	1	Mode 3:	TL0 is an 8-bit timer/counter. TH0 is an 8-bit timer
					using timer 1’s TR1 and TF1 bits.

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