10 I/O PORTS (P)
10-14
EPSON
S1C17704 TECHNICAL MANUAL
0x5203/0x5213/0x5223/0x5233: P
x
Port Pull-up Control Registers (P
x
_PU)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
P0 Port Pull-up
Control Register
(P0_PU)
0x5203
(8 bits)
D7–0
P0PU[7:0]
P0[7:0] port pull-up enable
1 Enable
0 Disable
1
(0xff)
R/W
P1 Port Pull-up
Control Register
(P1_PU)
0x5213
(8 bits)
D7–0
P1PU[7:0]
P1[7:0] port pull-up enable
1 Enable
0 Disable
1
(0xff)
R/W
P2 Port Pull-up
Control Register
(P2_PU)
0x5223
(8 bits)
D7–0
P2PU[7:0]
P2[7:0] port pull-up enable
1 Enable
0 Disable
1
(0xff)
R/W
P3 Port Pull-up
Control Register
(P3_PU)
0x5233
(8 bits)
D7–4
–
reserved
–
–
–
0 when being read.
D3–0
P3PU[3:0]
P3[3:0] port pull-up enable
1 Enable
0 Disable
1
(0xff)
R/W
Note
: The letter ‘
x
’ in bit names, etc., denotes a port number from 0 to 3.
D[7:0] P
x
PU[7:0]: P
x
[7:0] Port Pull-up Enable Bits
(P3PU[3:0] for the P3 ports)
Enables/disables the pull-up resistor incorporated in each port.
1 (R/W): Enable (default)
0
(R/W):
Disable
The
P
x
PU[7:0] bits are the pull-up control bits corresponding to the P
x
[7:0] ports respectively. When
a bit is set to 1, the pull-up resistor is enabled and the corresponding I/O port is pulled up during input
mode; if it is set to 0, the I/O port is not pulled up.
When the port is in output mode, the P
x
PU[7:0] settings are ignored and the port is not pulled up.
For unused ports, enable the pull-up resistors.
The pull-up settings are effective even if the port pin is configured for a peripheral module.
When changing the port pin from low level to high level with the built-in pull-up resistor, a delay in
the waveform rise time will occur depending on the time constant of the pull-up resistor and the load
capacitance of the pin. Therefore it is necessary to set an appropriate wait time for reading an I/O port.
This wait time should be the amount of time or more calculated by the following expression.
Wait time = R
IN
×
(C
IN
+ load capacitance on the board)
×
1.6 [seconds]
R
IN
: Pull-up resistance Max. value
C
IN
: Pin capacitance Max. value
Содержание S1C17704
Страница 1: ...TECHNICAL MANUAL S1C17704 CMOS 16 BIT SINGLE CHIP MICROCOMPUTER ...
Страница 22: ...1 OVERVIEW 1 10 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Страница 42: ...3 MEMORY MAP BUS CONTROL 3 12 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
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Страница 108: ...8 CLOCK GENERATOR CLG 8 8 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Страница 112: ...9 PRESCALER PSC 9 4 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Страница 138: ...10 I O PORTS P 10 26 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Страница 156: ...11 16 BIT TIMERS T16 11 18 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Страница 208: ...14 8 BIT OSC1 TIMER T8OSC1 14 16 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Страница 234: ...16 STOPWATCH TIMER SWT 16 14 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Страница 242: ...17 WATCHDOG TIMER WDT 17 8 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
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