W681308DG Datasheet, PDF (25/64 Pages) Nuvotem Talema – W681308 USB Audio Controller from Nuvoton integrates fast 8051 Microcontroller Unit (MCU)

W681308
XXXX PRODUCT DESCRIPTION
8.6.2
Timer/Counter 2
Timer/Counter 2 is a 16 bit up/down counter which is configured by the T2MOD register and controlled by the T2CON
register. Timer/Counter 2 is equipped with a capture/reload capability. As with the Timer 0 and Timer 1 counters, they
provide wide selection and control of the clock and selection of the operating modes. The clock source for Timer/ Counter 2
can be selected for the crystal oscillator, which is divided by 12 or 4 ( C/T2 = 0). The clock is then enabled when TR2 is a 1,
and disabled when TR2 is a 0.
C9H
T2MOD
T2CON
Bit 7
-
TF2
Bit 6
-
EXF2
Bit 5
-
RCLK
Bit 4
-
TCLK
Bit 3
T2CR
EXEN2
Bit 2
-
TR2
Bit 1
-
C/T2
Bit 0
DCEN
CP/RL2
Table 5 Timer 2 Mode/Control TMOD/TCON SFR
8.6.3
Watchdog Timer
The Watchdog timer is a free-running timer that can be programmed by the user to serve as a system supervisor, a time-
base generator or an event timer. It is basically a set of dividers that divide the system clock. The divider output is selectable
and determines the time-out interval. When the time-out occurs the flag WDIF is set, which can cause an interrupt if enabled,
and a system reset can also be caused if it is enabled. The interrupt will occur if the individual interrupt enable and the global
enable are set. The interrupt and reset functions are independent of each other and may be used separately or together
depending on the software employed.
Fosc
12/24/
0
48MHz
22
23 24
25
WD1,WD
0
00
01
10 ^Time-out
11
WDIF
EWD(EIE.4
)
WTRF
Interru
pt
Reset
Watchdog
PWT(WDCON.
26 27
512
clock
Res
delay
et
Enable Watchdog timer
reset
EWT(WDCON.1)
When used as a simple timer, the reset and interrupt functions are disabled. The timer will set the WDIF flag each time the
timer completes the selected time interval. The WDIF flag is polled to detect a time-out and the RWT allows software to
restart the timer. The Watchdog timer can also be used as a very long timer. The interrupt feature is enabled in this case.
Every time the time-out occurs an interrupt will occur if the global interrupt enable EA is set.
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Rev1.2