ht82k70e-l Holtek Semiconductor Inc., ht82k70e-l Datasheet - Page 19

• Manufacturer Part Number: ht82k70e-l
• Description: I/o Type 8-bit Otp Mcu
• Manufacturer: Holtek Semiconductor Inc.

bit high allows the Timer/Event Counter to run, clearing
the bit stops it running. If the Timer/Event Counter is in
the event count or pulse width measurement mode, the
active transition edge level type is selected by the logic
level of bit 3 of the Timer Control Register which is
known as T0E or T1E.
Configuring the Timer Mode
In this mode, the Timer/Event Counter can be utilised to
measure fixed time intervals, providing an internal inter-
rupt signal each time the Timer/Event Counter over-
flows. To operate in this mode, the Operating Mode
Select bit pair, T0M1/T0M0 or T1M1/T1M0, in the Timer
Control Register must be set to the correct value as
shown.
In this mode the internal clock is used as the internal
clock for the Timer/Event Counter. After the other bits in
the Timer Control Register have been setup, the enable
bit T0ON or T1ON, which is bit 4 of the Timer Control
Register, can be set high to enable the Timer/Event
Counter to run. Each time an internal clock cycle occurs,
the Timer/Event Counter increments by one. When it is
full and overflows, an interrupt signal is generated and
the Timer/Event Counter will reload the value already
loaded into the register and continue counting. The in-
terrupt can be disabled by ensuring that the Timer/Event
Counter Interrupt Enable bit in the Interrupt Control Reg-
ister, INTC0, is reset to zero.
Configuring the Event Counter Mode
In this mode, a number of externally changing logic
events, occurring on the external timer pin, can be re-
corded by the Timer/Event Counter. To operate in this
mode, the Operating Mode Select bit pair, T0M1/T0M0
or T1M1/T1M0, in the Timer Control Register must be
set to the correct value as shown.
Rev. 1.00
Control Register Operating Mode
Select Bits for the Timer Mode
Control Register Operating Mode
Select Bits for the Event Counter Mode
Event Counter Mode Timing Chart
Bit7 Bit6
Bit7 Bit6
Timer Mode Timing Chart
1
0
0
1
19
In this mode, the external timer pin, TMR0 or TMR1, is
used as the Timer/Event Counter clock source, however
it is not divided by the internal prescaler. After the other
bits in the Timer Control Register have been setup, the
enable bit T0ON or T1ON, which is bit 4 of the Timer
Control Register, can be set high to enable the
Timer/Event Counter to run. If the Active Edge Select bit
T0E or T1E, which is bit 3 of the Timer Control Register,
is low, the Timer/Event Counter will increment each time
the external timer pin receives a low to high transition. If
the Active Edge Select bit is high, the counter will incre-
ment each time the external timer pin receives a high to
low transition. When it is full and overflows, an interrupt
signal is generated and the Timer/Event Counter will re-
load the value already loaded into the preload register
and continue counting. The interrupt can be disabled by
ensuring that the Timer/Event Counter Interrupt Enable
bit in the Interrupt Control Register, INTC0, is reset to
zero.
As the external timer pin is an independent pin and not
shared with an I/O pin, the only thing to ensure the timer
operate as an event counter is to ensure that the Oper-
ating Mode Select bits in the Timer Control Register
place the Timer/Event Counter in the Event Counting
Mode. It should be noted that in the event counting
mode, even if the microcontroller is in the Power Down
Mode, the Timer/Event Counter will continue to record
externally changing logic events on the timer input pin.
As a result when the timer overflows it will generate a
timer interrupt and corresponding wake-up source.
Configuring the Pulse Width Measurement Mode
In this mode, the Timer/Event Counter can be utilised to
measure the width of external pulses applied to the ex-
ternal timer pin. To operate in this mode, the Operating
Mode Select bit pair, T0M1/T0M0 or T1M1/T1M0, in the
Timer Control Register must be set to the correct value
as shown.
Control Register Operating Mode
Select Bits for the Pulse Width Measure-
ment Mode
HT82K70E-L/HT82K76E-L
September 15, 2009
Bit7 Bit6
1
1