7 OSCILLATOR (OSC)
7-10
EPSON
S1C17704 TECHNICAL MANUAL
7.8 Noise Filters for RESET and NMI Inputs
If the RESET or NMI signal in the S1C17 Core input signals become active due to noise, the S1C17 Core executes
unnecessary reset ot NMI handling. To avoid this, the OSC module incorporates noise filters that operate with the
system clock to remove noise from these signals before they are input to the S1C17 Core.
The noise filter is provided for each signal, and can be enabled or bypassed individually.
RESET input noise filter: Noise will be removed when RSTFE (D1/OSC_NFEN register) = 1; the filter is bypassed
when RSTFE = 0.
NMI input noise filter:
Noise will be removed when NMIFE (D0/OSC_NFEN register) = 1; the filter is bypassed
when NMIFE = 0.
∗
RSTFE
: Reset Noise Filter Enable Bit in the Noise Filter Enable (OSC_NFEN) Register (D1/0x5062)
∗
NMIFE
: NMI Noise Filter Enable Bit in the Noise Filter Enable (OSC_NFEN) Register (D0/0x5062)
The noise filter operates with a divide-by-8 system clock (OSC3 or OSC1 clock). When it is enabled, pulses that
have a width of less than two cycles of this operating clock will be removed as noise. Therefore, 16 system clock
cycles or longer pulse width is required to accept as a valid signal.
Notes
: • Enable the filter for the RESET input under normal circumstances.
•
Although
the
S1C17704 has no external NMI input pin, the NMI request signal of the
watchdog timer pass through the filter.
Summary of Contents for S1C17704
Page 1: ...TECHNICAL MANUAL S1C17704 CMOS 16 BIT SINGLE CHIP MICROCOMPUTER ...
Page 22: ...1 OVERVIEW 1 10 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 42: ...3 MEMORY MAP BUS CONTROL 3 12 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 82: ...6 INTERRUPT CONTROLLER ITC 6 26 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 108: ...8 CLOCK GENERATOR CLG 8 8 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 112: ...9 PRESCALER PSC 9 4 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 138: ...10 I O PORTS P 10 26 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 156: ...11 16 BIT TIMERS T16 11 18 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 208: ...14 8 BIT OSC1 TIMER T8OSC1 14 16 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 234: ...16 STOPWATCH TIMER SWT 16 14 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 242: ...17 WATCHDOG TIMER WDT 17 8 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 264: ...18 UART 18 22 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 300: ...20 I2C 20 20 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 320: ...21 REMOTE CONTROLLER REMC 21 20 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 360: ...24 ON CHIP DEBUGGER DBG 24 6 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...
Page 362: ...25 BASIC EXTERNAL WIRING DIAGRAM 25 2 EPSON S1C17704 TECHNICAL MANUAL THIS PAGE IS BLANK ...