Port 10; Block Diagram Of P100 To P107 - NEC mPD780208 Subseries User Manual

4.2.8 Port 10

Port 10 is an 8-bit I/O port with an output latch. The P100 to P107 pins can be set to input mode/output mode
in 1-bit units using port mode register 10 (PM10). In mask ROM versions, use of pull-down resistors can be specified
in 1-bit units with the mask option. Pull-down resistor connection to V
The µ PD78P0208 does not contain pull-down resistors.
Port 10 can drive LEDs directly.
Alternate functions include VFD controller/driver display output.
RESET input sets port 10 to input mode.
Figure 4-11 shows a block diagram of port 10.
Caution Adjust the number of pull-down resistors so that the total power dissipation (refer to 15.10
Calculating Total Power Dissipation) is not exceeded.
RD
WR
PORT
WR
PM
PM: Port mode register
RD: Port 10 read signal
WR: Port 10 write signal
92
CHAPTER 4 PORT FUNCTIONS
Figure 4-11. Block Diagram of P100 to P107
Selector
Output latch
(P100 to P107)
PM100 to PM107
Alternate function
User's Manual U11302EJ4V0UM
or V can be specified in 4-bit units.
LOAD SS
Mask option
Only mask ROM versions.
µ
The PD78P0208 has no
pull-down resistors.
P100/FIP29
to
P107/FIP36
V
LOAD