NEC 78K0 Series User Manual page 118

5.2.7 Port 6
Port 6 is a 4-bit I/O port with an output latch. Port 6 can be set to the input mode or output mode in 1-bit units
using port mode register 6 (PM6).
The output of the P60 to P63 pins is N-ch open-drain output (6 V tolerance).
This port can also be used for serial interface data I/O, clock I/O, and external clock input.
Reset signal generation sets port 6 to input mode.
Figures 5-18 to 5-20 show block diagrams of port 6.
Remark When using P62/EXSCL0 as an external clock input pin of the serial interface, input a clock of 6.4 MHz
to it.
RD
WR
PORT
WR
PM
P6: Port register 6
PM6: Port mode register 6
RD: Read signal
WR××: Write signal
118
CHAPTER 5 PORT FUNCTIONS
Figure 5-18. Block Diagram of P60 and P61
Alternate
function
P6
Output latch
(P60, P61)
PM6
PM60, PM61
Alternate
function
Preliminary User's Manual U17260EJ3V1UD
P60/SCL0,
P61/SDA0