Port 1 - NEC mPD780024AS Series Preliminary User's Manual

WR
PU
PU00 to PU03
RD
WR
PORT
WR
PM
PM00 to PM03
PU: Pull-up resistor option register
PM: Port mode register
RD: Port 0 read signal
WR: Port 0 write signal

4.2.2 Port 1

Port 1 is an 4-bit input-only port.
This port can also be used as an A/D converter analog input.
Figure 4-3 shows a block diagram of port 1.
RD: Port 1 read signal
Caution When port 1 is used as a input port, the input value can be read using an 8-bit memory
manipulation instruction. However, in this case, do not use the higher 4 bits (P17 to P14)
because they are undefined.
manipulation instruction.
76
CHAPTER 4 PORT FUNCTIONS
Figure 4-2. Block Diagram of P00 to P03
Alternate
function
Output latch
(P00 to P03)
Figure 4-3. Block Diagram of P10 to P13
RD
Also, do not read the higher 4 bits using a 1-bit memory
Preliminary User's Manual U16035EJ1V0UM
V
DD0
P-ch
P00/INTP0 to
P02/INTP2,
P03/INTP3/ADTRG
P10/ANI0 to
P13/ANI3