King Billion Electronics Co., Ltd.
HE89C21
駿 億 電 子 股 份 有 限 公 司
HE80000 SERIES
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 contents of T2H and
T2L almost loaded into
Timer2 immediately
when Timer2 is turned on
after reset.
T2H
T2L
Auto reload when
Timer2 underflow
"Timer2 Counter"
decreases 1
No
Count TO
0xFFFFh
Yes
Start Timer2
Interrupt Request.
T2_INT
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
T2H
OP1
0x05
0x06
0x09
T2L[7:0]
T2H[7:0]
TC2E
7~0
7~0
3
W
W
Low byte of TC2 pre-load value
High byte of TC2 pre-load value
R/W 0: TC2 is disabled. (default)
1: TC2 is enabled.
The TB timer is used to generate time-out interrupt at fixed period. The time-out frequency of TB is
determined by dividing slow clock with a factor selected in OP2[3..0]. TBE (Time Base Enable) bit
January 20, 2003
11
V1.0E
KB [ King blillion Electronics Co.,Ltd. ]
