APPENDIX C POWER SAVING
AP-32
EPSON
S1C17704 TECHNICAL MANUAL
The peripheral modules listed below operate with a clock other than PCLK except for accessing their control
registers. Therefore, PCLK is not required after the control registers are set once and the module starts
operating.
- Clock timer
- Stopwatch timer
-
Watchdog
timer
- 8-bit OSC1 timer
- LCD driver
While PCLK is stopped, no maskable interrupt can be generated. Maskable interrupts are put on hold until
PCLK supply is resumed.
Table C.1.1 lists the clock control conditions and how to suspend/resume the CPU operation.
Table C.1.1 List of Clock Control Conditions
Current
consumption
OSC1
OSC3
CPU
(CCLK)
PCLK
peripherals
OSC1
peripherals
CPU suspending
method
CPU resuming
method
↑
Low
Stop
Stop
Stop
Stop
Stop
slp
instruction
1
Oscillating
(System clock)
Stop
Stop
Stop
Run
halt
instruction
1, 2
Oscillating
(System clock)
Stop
Stop
Run
Run
halt
instruction
1, 2, 3
Oscillating
(System clock)
Stop
Run (1/1)
Run
Run
Oscillating
Oscillating
(System clock)
Stop
Run
Run
halt
instruction
1, 2, 3
Oscillating
Oscillating
(System clock)
Run (low gear)
Run
Run
High
↓
Oscillating
Oscillating
(System clock)
Run (1/1)
Run
Run
Clearing HALT and SLEEP modes (CPU resuming methods)
1. Resuming by a port
The CPU resumes operating by occurrence of a cause of I/O port interrupt or a debug interrupt (issuing an
ICD forced break). If the interrupt controller or the IE flag in the CPU has been set to disable the I/O port
interrupt, the CPU does not accept the interrupt request and starts executing the instructions that follow the
halt
or
slp
instruction. When the interrupt has been enabled and PCLK was activated before the
halt
or
slp
instruction is executed, the CPU executes the interrupt handler. When PCLK was stopped before the
halt
or
slp
instruction is executed, the interrupt is put on hold until PCLK supply is resumed even if the
interrupt has been enabled.
2. Resuming by an OSC1 peripheral
The CPU resumes operating by occurrence of a cause of clock timer, stopwatch timer, watchdog timer, or
8-bit OSC1 timer interrupt. If the interrupt controller or the IE flag in the CPU has been set to disable these
interrupts, the CPU does not accept the interrupt request and starts executing the instructions that follow the
halt
instruction. When the interrupt has been enabled and PCLK was activated before the
halt
instruction
is executed, the CPU executes the interrupt handler. When PCLK was stopped before the
halt
instruction is
executed, the interrupt is put on hold until PCLK supply is resumed even if the interrupt has been enabled.
3. Resuming by a PCLK peripheral
The CPU resumes operating by occurrence of a cause of interrupt in a PCLK peripheral whose interrupt is
enabled by the interrupt controller. If the IE flag in the CPU has been set to 0, the CPU does not accept the
interrupt request and starts executing the instructions that follow the
halt
instruction. If the IE flag has been
set to 1, the CPU executes the interrupt handler.
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 ...