Port 2 - NEC mPD780852 Series Preliminary User's Manual

4.2.3 Port 2

Port 2 is an 8-bit output only port with output latch. P20 to P27 pins go into a high-impedance state when the ENn
of port mode control register (PMC) is set to 0 and the port mode register 2 (PM2) is set to 1.
Alternate functions include meter control PWM output.
RESET input sets port 2 to high-impedance state.
Figure 4-4 shows a block diagram of port 2.
RD
WR
PORT
WR
PM
PM: Port mode register
RD: Port 2 read signal
WR: Port 2 write signal
Caution When PM2 is set to 0, read operation is enabled. When PM2 is set to 1, read operation is disabled.
Remark n = 1, 2
CHAPTER 4 PORT FUNCTIONS
Figure 4-4. P20 to P27 Block Diagram
Output latch
(P20 to P27)
PM20 to PM27
Alternate
functions
Preliminary User's Manual U14581EJ3V0UM00
Decoder
2
MODn ENn DIRn1 DIRn0
P20/SM11 to P23/SM14
P24/SM21 to P27/SM24
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