Pin Name I/O
Configuration
Option
Description
PG0/INT I/O Pull-high
Bidirectional 1-bit input/output port. Software instructions
determine if the pin is a CMOS output or Schmitt Trigger in
-
put. A configuration option determines if the pin has a
pull-high resistor. PG0 is pin-shared with external interrupt
pin INT
. The external interrupt input is activated on a high to
low transition.
OSC1/PG1
OSC2/PG2
I
O
Pull-high
Crystal or RC or
Int. RC+I/O or
Int. RC+RTC
OSC1, OSC2 are connected to an external RC network or
external Crystal (determined by configuration option) for
the internal system clock. For external RC system clock op
-
eration, OSC2 is an output pin for 1/4 system clock.
These two pins can also be optioned as an RTC oscillator
(32768Hz) or I/O lines. In these two cases, the system
clock comes from an internal RC oscillator whose nominal
frequency at 5V has 4 options, 3.2MHz, 1.6MHz, 800kHz,
400kHz. If the pins are used as normal I/O pins, then
pull-high options are available. If used as oscillator pins,
bits PG1 and PG2 will be free for use by the application pro
-
gram. In this case the pull-high options are disabled.
RES I
¾
Schmitt Trigger reset input. Active low.
VDD
¾¾
Positive power supply
VSS
¾¾
Negative power supply, ground
Note 1. Each pin on PA can be programmed through a configuration option to have a wake-up function.
2. Individual pins cannot be selected to have pull-high resistors. If the pull-high configuration
is chosen for a particular port, then all input pins on this port will be connected to pull-high
resistors.
3. Pins PC1 and PC3~PC5 only exist on the 28-pin package. On the 24-pin package, these pins
are not available.
HT48R50A-1/HT48C50-1
Pin Name I/O
Configuration
Option
Description
PA0~PA7 I/O
Pull-high
Wake-up
Schmitt Trigger
Bidirectional 8-bit input/output port. Each pin can be con
-
figured as a wake-up input by configuration option. Soft
-
ware instructions determine if the pin is a CMOS output or
input. Configuration options determine if all pins on this
port have pull-high resistors and if the inputs are Schmitt
Trigger or non Schmitt Trigger.
10
I/O Type MCU
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