NO:
W90P710 Programming Guide
VERSION:
2.0
PAGE:
156
The above information is the exclusive intellectual property of Winbond Electronics and shall not be disclosed, distributed or reproduced without permission
from Winbond.
Table No.: 2005-W90P710-11-A
TDR1
0xFFF8.1014 R
Timer Data Register 1
0x0000.0000
TISR
0xFFF8.1018 R/C
Timer Interrupt Status Register
0x0000.0000
WTCR
0xFFF8.101C R/W
Watchdog Timer Control Register
0x0000.0000
12.4 Functional Descriptions
12.4.1 Interrupt
Frequency
The frequency of timer interrupt depends on the following equation :
Freq. = Crystal clock / ((pre-1) * counter))
For W90P710, the crystal clock input is 15 MHZ. According to the equation, user can decide the
values of pre-scalar and counter to get the desired interrupt frequency. Table 4-1demonstrates
several reference values.
Table 12-1 Timer Reference Setting Values
Frequency (1/sec) [Pre-Scalar]
[Counter]
18
0 0xCB735
40
0 0x5B8D8
100
0 0x249F0
12.4.2 Initialization
The driver should set the operating mode, pre-scalar and counter before enable the timer
interrupt. The Timer supports
one-shot
,
periodic
and
toggle
mode for user to implement the counting
scheme.
•
In
one-shot
mode, the interrupt signal is generated once and it’s not happen again unless the
timer is re-enabled later.
