HT49R50 Holtek Semiconductor Inc, HT49R50 Datasheet - Page 23

• Manufacturer Part Number: HT49R50
• Description: 8-Bit Microcontroller
• Manufacturer: Holtek Semiconductor Inc

further transient pulse. In this operation mode,
the timer/event counter begins counting accord-
ing not to the logic level but to the transient
edges. In the case of counter overflows, the coun-
ter is reloaded from the timer/event counter
preload register and issues an interrupt request,
as in the other two modes, i.e., event and timer
modes.
To enable the counting operation, the Timer ON
bit (TON; bit 4 of TMR0C or TMR1C) should be
set to 1. In the pulse width measurement mode,
the TON is automatically cleared after the
measurement cycle is completed. But in the
other two modes, the TON can only be reset by
(TMR0C)
TE
TON
TN2
TN0
TN1
Label
¾
Bits
0~2 Unused bits, read as ²0²
3
4
5
6
7
To define the TMR0 active edge of timer/event counter
(0=active on low to high; 1=active on high to low)
To enable/disable timer counting
(0=disabled; 1=enabled)
2 to 1 multiplexer control inputs to select the timer/event counter clock source
(0=RTC outputs; 1= system clock or system clock/4)
To define the operating mode (TN1, TN0)
01= Event count mode (External clock)
10= Timer mode (Internal clock)
11= Pulse Width measurement mode (External clock)
00= Unused
Timer/event counter 1
TMR0C register
23
instructions. The overflow of the timer/event
counter 0/1 is one of the wake-up sources and
can also be applied to a PFD (Programmable
Frequency Divider) output at PA3 by mask op-
tion. Only one PFD (PFD0 or PFD1) can be ap-
plied to PA3 by mask option . No matter what the
operation mode is, writing a 0 to ET0I or ET1I
disables the related interrupt service. When the
PFD function is selected, executing ²CLR [PA].3²
instruction to enable PFD output and executing
²SET [PA].3² instruction to disable PFD output.
In the case of timer/event counter OFF
condition, writing data to the timer/event counter
preload register also reloads that data to the
Function
August 18, 1999
HT49C50