HT46R068B/HT46R069B
Enhanced A/D Type 8-bit OTP MCU
Wake-up Function Register – PAWK
When the microcontroller enters the Idle/Sleep Mode, various methods exist to wake the device
up and continue with normal operation. One method is to allow a falling edge on the I/O pins to
have a wake-up function. This register is used to select which Port A I/O pins are used to have this
wake-up function.
Pull-high Registers – PAPU, PBPU, PCPU, PDPU, PEPU, PFPU
The I/O pins, if configured as inputs, can have internal pull-high resistors connected, which eliminates
the need for external pull-high resistors. This register selects which I/O pins are connected to internal
pull-high resistors.
Software COM Register – SCOMC
The pins PB0~PB3 on Port B can be used as SCOM lines to drive an external LCD panel. To
implement this function, the SCOMC register is used to setup the correct bias voltages on these
pins.
Oscillator
Various oscillator options offer the user a wide range of functions according to their various
application requirements. The flexible features of the oscillator functions ensure that the best
optimisation can be achieved in terms of speed and power saving. Oscillator selections and
operation are selected through a combination of configuration options and registers.
System Oscillator Overview
In addition to being the source of the main system clock the oscillators also provide clock sources
for other functions such as the Watchdog Timer, Timer/Event Counter, Time Base etc. The system
oscillator can be provided from a choice of three high speed oscillators, the HXT, ERC or HIRC
oscillators, or a single low speed, LXT crystal oscillator. The LIRC oscillator is used only as a
Watchdog Timer clock source.
Type
Name
Freq.
Pins
Function
OSC1/
OSCꢃ
Exteꢁnal Cꢁꢂstal
HXT 400kHz~1ꢃMHz
High Speed Sꢂstem Clock
Exteꢁnal RC
ERC 400kHz~1ꢃMHz OSC1
HIRC 4ꢅ 8 oꢁ 1ꢃMHz
High Speed Sꢂstem Clock
High Speed Sꢂstem Clock
Low Speed Sꢂstem Clock
Inteꢁnal Highb Speed RC
—
XT1/ Clock soꢀꢁce foꢁ: Watchdogꢅ Time
Exteꢁnal Low Speed Cꢁꢂstal LXT
3ꢃ7ꢄ8Hz
13kHz
XTꢃ
Baseꢅ Timeꢁ/Event Coꢀnteꢁs 0/1
Clock/SPI/SPIA
Inteꢁnal Low Speed RC
LIRC
—
Watchdog Timeꢁ Clock
External Crystal/Resonator Oscillator – HXT
The simple connection of a crystal across OSC1 and OSC2 will create the necessary phase shift
and feedback for oscillation. However, for some crystals and most resonator types, to ensure
oscillation and accurate frequency generation, it is necessary to add two small value external
capacitors, C1 and C2. The exact values of C1 and C2 should be selected in consultation with the
crystal or resonator manufacturer's specification.
Rev. 1.00
ꢃ8
�anꢀaꢁꢂ ꢃꢄꢅ ꢃ011
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
