10 I/O PORTS (P)
10-4
EPSON
S1C17704 TECHNICAL MANUAL
10.4 Pull-Up Control
The S1C17704 I/O ports have a built-in pull-up resistor and whether it is used or not can be selected using
P
x
PU[7:0] (P
x
_PU register) for each bit individually.
∗
P0PU[7:0]
: P0[7:0] Port Pull-up Enable Bits in the P0 Port Pull-up Control (P0_PU) Register (D[7:0]/0x5203)
∗
P1PU[7:0]
: P1[7:0] Port Pull-up Enable Bits in the P1 Port Pull-up Control (P1_PU) Register (D[7:0]/0x5213)
∗
P2PU[7:0]
: P2[7:0] Port Pull-up Enable Bits in the P2 Port Pull-up Control (P2_PU) Register (D[7:0]/0x5223)
∗
P3PU[3:0]
: P3[3:0] Port Pull-up Enable Bits in the P3 Port Pull-up Control (P3_PU) Register (D[3:0]/0x5233)
The pull-up resistor is enabled by setting P
x
PU[7:0] to 1 (default), and the port pin will be pulled up when the port
is in input mode. When set to 0, the pull-up resistor is disabled.
When the port is in output mode, the P
x
PU[7:0] settings are ignored and the pull-up resistor is disabled.
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 ...
Страница 82: ...6 INTERRUPT CONTROLLER ITC 6 26 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
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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Страница 320: ...21 REMOTE CONTROLLER REMC 21 20 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Страница 360: ...24 ON CHIP DEBUGGER DBG 24 6 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Страница 362: ...25 BASIC EXTERNAL WIRING DIAGRAM 25 2 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...