NEC 78K0 Series User Manual page 102

5.2.1 Port 0
Port 0 is a 7-bit I/O port with an output latch. Port 0 can be set to the input mode or output mode in 1-bit units
using port mode register 0 (PM0). When the P00 to P06 pins are used as an input port, use of an on-chip pull-up
resistor can be specified in 1-bit units by pull-up resistor option register 0 (PU0).
This port can also be used for timer I/O, serial interface data I/O, clock I/O, and chip select input.
Reset signal generation sets port 0 to input mode.
Figures 5-2 to 5-7 show block diagrams of port 0.
Caution To use P02/SO11
register 11 (CSIM11) and serial clock selection register 11 (CSIC11) to the default status (00H).
Note Available only in the
WR
PU
RD
WR
PORT
WR
PM
P0: Port register 0
PU0: Pull-up resistor option register 0
PM0: Port mode register 0
RD: Read signal
WR××: Write signal
102
CHAPTER 5 PORT FUNCTIONS
Note Note
and P04/SCK11
µ
PD78F0534, 78F0535, 78F0536, 78F0537, and 78F0537D.
Figure 5-2. Block Diagram of P00
PU0
PU00
Alternate function
P0
Output latch
(P00)
PM0
PM00
Preliminary User's Manual U17260EJ3V1UD
as general-purpose ports, set serial operation mode
EV
DD
P-ch
P00/TI000