HD404818 Datasheet, PDF (52/100 Pages) Hitachi Semiconductor – 16-digit LCD driver

HD404818 Series
according to the value of timer load register C. If it is not selected, timer C goes to $00. The timer C
interrupt request flag (IFTC: $002, bit 2) will be set as this overflow is output.
Timer C is also available as a watchdog timer for detecting runaway programs. MCU reset occurs when the
watchdog on flag (WDON) is 1 and the counter overflow output is generated by a runaway program. If
timer C stops, the watchdog timer function also stops. In the standby mode, this function is enabled.
Timer C provides a variable duty-cycle pulse output function (PWM). The output waveform differs
depending on the contents of the timer mode register and timer load register C (figure 28). When selecting
the pulse output function, set R3₁/TIMO to TIMO by controlling port mode register B.
When timer C stops, this functions also stops.
Watchdog on
flag (WDON)
System
reset signal
Watchdog timer
control logic
Timer C interrupt
request flag
(IFTC)
TIMO
Timer output
control logic
Timer latch register CU (TLCU)
Selector
System ^fcyc/fSUB
clock _{(tcyc/tsubcyc)}
Prescaler S (PSS)
Clock
Timer latch
register CL
(TLCL)
Timer counter C
(TCC)
Overflow
Timer load
register CU
(TCRU)
Free-running/
reload control
Timer load
register CL
(TCRL)
3
Timer mode
register C
(TMC)
Figure 27 Timer C Block Diagram
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