9 PRESCALER (PSC)
S1C17704 TECHNICAL MANUAL
EPSON
9-1
9 Prescaler (PSC)
9.1 Configuration of the Prescaler
The S1C17704 incorporates a prescaler for generating the source clock of the timers and other peripheral modules.
The prescaler divides the PCLK clock, which is supplied from the clock generator, by 1 to 16K to generate 15
clocks with different frequencies. A clock select register is provided for each destination peripheral module
allowing selection of a prescaler output clock as the count or operating clock.
1/1
PCLK
Debug
status signal
PSC
1/2
1/4
1/8
1/16 1/32 1/64 1/128
1/256 1/512 1/1K 1/2K 1/4K 1/8K 1/16K
UART
SPI
I
2
C
8-bit timer
16-bit timer Ch.0
16-bit timer Ch.1
16-bit timer Ch.2
PWM & capture timer
Remote controller
P port
Figure 9.1.1 Prescaler
The prescaler is controlled by the PRUN bit (D0/PSC_CTL register). Write 1 to PRUN to run the prescaler and
write 0 to stop the prescaler. When the timer and interface modules are idle, stop the prescaler to reduce current
consumption. At initial reset, the prescaler stops operating.
∗
PRUN
: Prescaler Run/Stop Control Bit in the Prescaler Control (PSC_CTL) Register (D0/0x4020)
Note
: Supply PCLK from the clock generator before the prescaler can be used.
The prescaler provides one more control bit PRUND (D1/PSC_CTL register). This bit is used to specify the
prescaler operation in debug mode. If PRUND is set to 1, the prescaler operates in debug mode. If PRUND is set to
0, the prescaler stops operating when the S1C17 Core enters debug mode. Set PRUND to 1 when using a timer or
interface module in debug mode.
∗
PRUND
: Prescaler Run/Stop Setting Bit in Debug Mode in the Prescaler Control (PSC_CTL) Register (D1/0x4020)
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 ...