King Billion Electronics Co., Ltd

駿

億

電

子

股

份

有

限

公

司

HE83005

HE80000 SERIES

July 28, 2003

7

V3.4

This specification is subject to change without notice. Please contact sales person for the latest version before use.

T1H

T1L

< Timer1 Counter >

Decreases 1

Count To

0xFFFFh

The contents of

T1H and T1L are

almost loaded into

Timer1 immediately

when Timer1 is

enabled after reset.

Auto reload

when Timer1

is underflow

Yes

No

Timer1

Interrupt

Request

T1_INT

8. Timer2

Timer2 is similar in structure to Timer1 except that clock source of Timer2 comes from the system clock

“Fsys”/1.5. The system clock “Fsys” varies depending on the operation modes of the MCU.

The Timer2 consists of two 8-bit write-only preload registers T2H and T2L and 16-bit down counter. If

Timer2 is enabled, counter will decrement by one with each incoming clock pulse. Timer2 interrupt will

be generated when the counter underflows - counts down to FFFFH. And it will be automatically reloaded

with the value of T2H and T2L.

Please note that the interrupt signal is generated when counter counts from 0000H to FFFFH. If the value

of counter is N, and count down to FFFFH, the total count is N+1. The content of counter is zero when

system resets. Once it is enabled to count at this time, the interrupt will be generated immediately and

value of T2H and T2L will be loaded since the counter counts to FFFFH. So the T2H and T2L value

should be set before enabling Timer2.

The Timer2 related control registers are list as below:

Register

Address

Field

Bit Position

Mode

Description

IER

0x02

TC2_IER

1

R/W

0: TC2 interrupt is disabled. (default)

1: TC2 interrupt is enabled.

T2L

0x05

T2L[7:0]

7~0

W

Low byte of TC2 pre-load value

T2H

0x06

T2H[7:0]

7~0

W

High byte of TC2 pre-load value

OP1

0x09

TC2E

3

R/W

0: TC2 is disabled. (default)

1: TC2 is enabled.