Chapter 1 Hardware Structure
Bidirectional 8-bit input/output port. Each pin on this
port can be configured as a wake-up input by a con-
figuration option. Configuration options determine
whether pins PA0~PA3 are configured as CMOS out-
puts or NMOS input/output pins. If PA0~PA3 are con-
CMOS or NMOS figured as NMOS input/output pins, then pull-high
options are available but apply to all 4 pins, not indi-
PA0/PA1 or BZ/BZ vidual pins. Pins PA4~PA7 are always configured as
NMOS input/output pins with pull-high resistors con-
PA3 or PFD
nected. All inputs are Schmitt Trigger types. Pins
PA0, PA1 and PA3 are pin-shared with BZ, BZ and
PFD respectively, the function of which is chosen via
6-bit Schmitt Trigger input port. Each input pin is con-
nected to an internal pull-high resistor. PB0, PB1 and
PB2 are pin-shared with INT0, INT1 and TMR re-
LCD power supply for HT49R30A-1/HT49C30-1.
LCD voltage pump for HT49C30L.
LCD voltage pump for HT49R30A-1/HT49C30-1.
LCD power supply for HT49C30L.
LCD voltage pump
The 1/4 LCD duty cycle configuration option will de-
termine whether pin COM3/SEG18 is configured as a
SEG18 segment driver or as a common COM3 output
driver for the LCD panel. COM0~COM2 are the LCD
LCD driver outputs for LCD panel segments
OSC1 and OSC2 are connected to an external RC
network or external crystal (determined by configura-
tion option) for the internal system clock. For external
RC system clock operation, OSC2 is an output pin for
1/4 system clock. If an RTC oscillator on pins OSC3
and OSC4 is used as a system clock, then the OSC1
and OSC2 pins should be left floating.
OSC3 and OSC4 are connected to a 32768Hz crystal
to form a Real Time Clock for timing purposes or to
form a system clock.
V1, C1, C2
1/2, 1/3 or 1/4
Crystal or RC