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4.2.7 Port 9
Port 9 is an 8-bit output-only port. 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
µ PD78P0208 does not contain pull-down resistors.
Port 9 can drive LEDs directly.
Alternate functions include VFD controller/driver display output.
RESET input sets port 9 to output mode.
Figure 4-10 shows a block diagram of port 9.
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.
WR
PORT
WR: Port 9 write signal
CHAPTER 4 PORT FUNCTIONS
Figure 4-10. Block Diagram of P90 to P97
Output latch
(P90 to P97)
Alternate function
User's Manual U11302EJ4V0UM
or V
can be specified in 4-bit units. The
LOAD
SS
P-ch open-drain
P90/FIP21
P97/FIP28
V
Mask option
Only mask ROM versions.
µ
The
PD78P0208 has
no pull-down resistors.
to
LOAD
91
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