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Rev. 1.00
117 of ���
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Standard 8051 8-Bit Flash MCU
HT85F2260/HT85F2270/HT85F2280
Interrupts
Input/Output Ports
26
Input/Output Ports
The devices offer a range of flexible options on their I/O ports. Many pins can be setup with a
choice of different register controlled modes as well as having pull-high wake up and slew rate
functions.
Input/Output Port Overview
The devices are provided with a series bidirectional input/output ports labeled with port names
P0~P5. These I/O ports are mapped to the Special Function Registers with specific addresses as
shown in the Special Function Registers table. All of these I/O ports can be used for both input and
output operations, the data for which is stored in Port Data Registers. Ports P0~P3 can be setup
using Port Mode Registers to operate in a series of different modes. Ports 4 and 5 can only operate
in the traditional 8051 type quasi-bidirectional mode. The Port P0 provides register controlled wake
up function as well. Bit manipulation instructions can be used to control Ports P0~P3, while Ports
4 and 5 must be controlled using byte wide instructions.
I/O Port Function Summary
Function.
Port Number
P0
P1
P2
P3
P4
P5
Notes
P�sh-P�ll
√
√
√
√
—
—
CMOS O�tp�t
Open D�ain
√
√
√
√
—
—
NMOS
Q�asi Bi-di�ect
√
√
√
√
√
√
T�aditional 80�1 Po�t t�pe
Inp�t Onl�
√
√
√
√
—
—
High impedance
Bit Add�essable
√
√
√
√
—
—
—
Slew Rate Cont�ol
√
√
√
√
√
√
Fast o� Slow select