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CHAPTER 4 PORT FUNCTIONS
Preliminary User’s Manual U16035EJ1V0UM
Figure 4-2. Block Diagram of P00 to P03
Internal bus
V
DD0
P-ch
P00/INTP0 to
P02/INTP2,
P03/INTP3/ADTRG
WR
PU
RD
WR
PORT
WR
PM
PU00 to PU03
Alternate
function
Output latch
(P00 to P03)
PM00 to PM03
Selector
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.
Figure 4-3. Block Diagram of P10 to P13
RD
P10/ANI0 to
P13/ANI3
Internal bus
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. Also, do not read the higher 4 bits using a 1-bit memory
manipulation instruction.