Timer 2 (24-Bit Timer, 8-Bit Prescaler + 16-Bit Timing); Auxiliary Register 1 (Auxr); External Interrupt And Clock Output Control Register (Intclko); Timer 2 Counting Registers - STC micro STC8A8K64D4 Series Reference Manual

STC8A8K64D4 Series Manual

13.3 Timer 2 (24-bit timer, 8-bit prescaler + 16-bit timing)

13.3.1 Auxiliary Register 1 (AUXR)

Symbol Address
AUXR 8EH
TR2: T2 run control bit.
0: T2 stops counting.
1: T2 start counting.
T2_C/T: T2 mode select bit.
0: T2 is used as a timer (input pulse is from internal system clock);
1: T2 is used as a counter (input pulse is from external T2/P1.2 pin).
T2x12: T2 speed control bit.
0: The clock source of T2 is SYSclk/12.
1: The clock source of T2 is SYSclk/1.

13.3.2 External Interrupt and Clock Output Control Register (INTCLKO)

Symbol Address
INTCLKO 8FH
T2CLKO: T2 clock out control bit.
0: Turn off the clock output.
1: P1.3 is configured for T2 clock output pin. When T2 overflows, P1.3 will flip automatically.

13.3.3 Timer 2 Counting Registers

Symbol Address
T2L D7H
T2H D6H
T2 operates in 16-bit auto-reload mode. T2L and T2H combine into a 16-bit register with T2L as the low byte and
T2H as the high byte. When the 16-bit counter [T2H, T2L] overflows, the system loads the reload value in the
internal 16-bit reload register into [T2H, T2L] automatically.

13.3.4 Timer 2 8-bit Prescaler Register (TM2PS)

Symbol Address
TM2PS FEA2H
Timer 2 clock ＝ SYSclk ÷( TM2PS + 1 )

13.3.5 Timer 2 working mode

The functional block diagram of Timer/Counter 2 is as follows.
B7 B6
T0x12 T1x12 UART_M0x6
B7 B6
- EX4
B7 B6
B7 B6
B5 B4 B3
T2R T2_C/T
B5 B4 B3
EX3 EX2 -
B5 B4 B3
B5 B4 B3
B2 B1 B0
T2x12 EXTRAM S1ST2
B2 B1 B0
T2CLKO T1CLKO T0CLKO
B2 B1 B0
B2 B1 B0
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