W83L951DG Datasheet, PDF (69/112 Pages) Winbond – Mobile Keyboard and Embedded Controller

W83L951DG/W83L951FG
6.8 Timer Block
The Keyboard controller has four timers: timer X, timer Y, timer 1, and timer 2. The division ratio of
each timer or pre-scalar is given by 1/n + 1, where n is the value in the corresponding timer or pre-
scalar latch. All timers are count down. When the timer reaches "00H", an underflow occurs at the next
count pulse and the corresponding timer latch is reloaded into the timer and the count is continued.
When a timer is underflow, the corresponding interrupt request bit is set to 1.
In Timer 1 and Timer 2, the count source of pre-scalar 1/2 is the oscillator frequency divided by 16.
The output of pre-scalar 1/2 is counted for both timer 1 and 2, and a timer underflow sets the interrupt
request bit.
Timer X and Timer Y can works in one of four operating modes by setting the timer XY mode register.
Table 6-16.Timer Register Define
TIMER BLOCK(9)
EXTADDR NAME
7
6
5
4
10
PRE1 TM1ST Prescale 1 [6:0]
11
T1
Timer 1 [7:0]
12
PRE2 TM2ST Prescale 2 [6:0]
13
T2
Timer 2 [7:0]
18
TM
TMYST CNTR1 TMYMODE
19
PREX Prescale X [7:0]
1A
TX
Timer X[7:0]
1B
PREY Prescale Y [7:0]
1C
TY
Timer Y [7:0]
3
2
1
0
TMXST CNTR0 TMXMODE
6.8.1 Register Description
6.8.1.1 Clock Prescale Number of Timer 1 (PRE1) (Default Value: 0111_1111)
Bit 7: Timer 1 Start Bit
Write: Start Timer 1 counter.
1: Enable (Prescale Counter Reload & Start, but Timer 1 Data Keep)
0: Disable
Read: Always Read ‘LOW’.
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Publication Release Date: August 2006
Revision 1.0