EM78159NAS EMC [ELAN Microelectronics Corp], EM78159NAS Datasheet - Page 20

• Manufacturer Part Number: EM78159NAS
• Description: 8-Bit Microcontroller with OTP ROM
• Manufacturer: EMC [ELAN Microelectronics Corp]

EM78P159N
8-Bit Microcontrollerwith OTP ROM
16 •
4.4 I/O Ports
The I/O registers, both Port 5 and Port 6, are bi-directional tri-state I/O ports. Port 6 can
be pulled high internally by software. In addition, Port 6 can also features an
open-drain output through software and an Input status change interrupt (or wake-up)
function. P50 ~ P53 and P60 ~ P63 pins can be pulled down by software. Each I/O pin
can be defined as "input" or "output" pin by the I/O control register (IOC5 ~ IOC6).
P50~P51 are the R-option pins enabled by setting the ROC bit in the IOCE register to
“1.” When the 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 (Figures 4-3,
4-4a, 4-4b, & 4-5).
P O R T
Figure 4-3 I/O Port and I/O Control Register for Port 5 Circuit
Pull-down is not shown in the figure.
0
1
M
U
X
(This specification is subject to change without further notice)
NOTE
Q
Q
Q
_
Q
P C R D
_
C
R
C
P
R
L
P
L
C L K
C L K
D
D
Product Specification (V1.0) 03.10.2006
P D R D
PC W R
PD W R
IO D