8-Bit Microcontroller with OTP ROM Specification Sheet

EM78P447N
8-Bit Microcontroller with OTP ROM
16 •
Product Specification (V1.1) 03.30.2005
(This specification is subject to change without further notice)
4.4 I/O Ports
The I/O registers, Port 5, Port 6, and Port 7, are bi-directional tri-state I/O ports. The
functions of Pull-high, R-option, and Open-drain can be performed internally by CONT
and IOCE respectively. There is input status change wake-up function on Port 6, P74,
and P75. Each I/O pin can be defined as "input" or "output" pin by the I/O control
register (IOC5 ~ IOC7). The I/O registers and I/O control registers are both readable
and writable. The I/O interface circuits for Port 5, Port 6, and Port 7 are shown in
Figures. 7(a) and (b) respectively.
PDRD
Q
Q
CLK
D
PCWR
PDWR
Q
Q
CLK
D
PR
CL
PORT
0
1
M
U
X
IOD
PCRD
PR
CL
Fig. 7 (a) The I/O Port and I/O Control Register Circuit
PDRD
Q
Q
CLK
D
PCWR
PDWR
Q
Q
CLK
D
0
1
M
U
X
IOD
ROC
VCC
Weakly
Pull-up
PORT
Rex*
*The Rex is 430K ohm external resistor
PCRD
PR
CL
PR
CL
Fig.7 (b) The I/O Port with R-Option (P70, P71) Circuit