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CHAPTER 5 PORT FUNCTIONS
5.2.8 Port 8
Port 8 is a 7-bit input/output port with output latch. P81 to P87 pins can specify the input mode/output mode in
1-bit units with the port mode register 8 (PM8).
Alternate functions also include segment signal output of the LCD controller/driver and prescaler signal output.
Segment output and input/output port can be switched by setting the LCD display control register (LCDC).
RESET input sets port 8 to input mode.
Figures 5-9 and 5-10 show block diagrams of port 8.
Figure 5-9. P81 Block Diagram
Figure 5-10. P82 to P87 Block Diagram
PM : Port mode register
RD : Port 8 read signal
WR : Port 8 write signal
RD
P81/S19/TPO
WR
PORT
WR
PM
PM81
Selector
Output latch
(P81)
Internal bus
Segment output
function
Alternate
functions
RD
P82/S18 to P87/S13
WR
PORT
WR
PM
PM82 to PM87
Selector
Output latch
(P82 to P87)
Internal bus
Segment output
function
Summary of Contents for mPD780973 Series
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