em78p156n ELAN Microelectronics Corp, em78p156n Datasheet - Page 17

• Manufacturer Part Number: em78p156n
• Description: 8-bit Micro-controller
• Manufacturer: ELAN Microelectronics Corp

This specification is subject to change without prior notice.
R-option function is used, it is recommended that P50~P51 are used as output pins. When R-option is in
enable state, P50~P51 must be programmed as input pins. Under R-option mode, the current/power
consumption by Rex should be taken into the consideration to promote energy conservation.
The I/O registers and I/O control registers are both readable and writable. The I/O interface circuits for
Port 5 and Port 6 are shown in the following Figures 6, 7(a), 7(b), and Figure 8.
P O R T
B i t 6 o f I O C E
P 6 0 / I N T
NOTE: Pull-high (down) and Open-drain are not shown in the figure.
P O R T
D
C L K
P
R
C
L
Fig. 7(a) The Circuit of I/O Port and I/O Control Register for P60 (/INT)
Q
Q
_
Fig. 6 The Circuit of I/O Port and I/O Control Register for Port 5
NOTE: Pull-down is not shown in the figure.
I N T
0
1
M
U
X
0
1
17
M
U
X
Q
Q
Q
_
Q
P C R D
_
D
C L K
C
R
C
P
R
L
P
L
Q
Q
Q
Q
P
R
C
L
_
_
C L K
C L K
P C R D
C L K
C L K
P
R
C
P
R
C
L
Q
Q
L
_
D
D
D
D
P D R D
PC W R
PD W R
P C W R
P D W R
P D R D
I O D
T 1 0
EM78P156N
IO D
OTP ROM
07.29.2004 (V1.2)