Port 4 - Renesas RL78/G1P Hardware User Manual

RL78/G1P

4.2.4 Port 4

Port 4 is an I/O port with an output latch. Port 4 can be set to the input mode or output mode using port mode register
4 (PM4). When the P40 pin is used as an input port, use of an on-chip pull-up resistor can be specified in 1-bit units by
pull-up resistor option register 4 (PU4).
This port can also be used for data I/O for a flash memory programmer/debugger.
Reset signal generation sets port 4 to input mode.
Name
P40
Caution When a tool is connected, the P40 pin cannot be used as a port pin.
Remark :
don't care
PM4: Port mode register 4
Figure 4-12 shows a block diagram of port 4.
WR
PU
RD
WR
PORT
WR
PM
P4: Port register 4
PU4: Pull-up resistor option register 4
PM4: Port mode register 4
RD: Read signal
WR: Write signal
R01UH0895EJ0100 Rev.1.00
Nov 29, 2019
Table 4-7. Settings of Registers When Using Port 4
I/O PM4
Input 1
Output 0
Figure 4-12. Block Diagram of P40
PU4
PU40
Alternate
function
P4
Output latch
(P40)
PM4
PM40
Alternate
function
CHAPTER 4 PORT FUNCTIONS
Alternate Function Setting


Remark
V
DD
P-ch
P40/TOOL0
79