12 8-BIT TIMER (T8F)
S1C17704 TECHNICAL MANUAL
EPSON
12-9
12.9 8-bit Timer Interrupt
The 8-bit timer outputs an interrupt request signal to the interrupt controller (ITC) when the counter underflows.
To generate a timer underflow interrupt, set up the interrupt level and enable the interrupt using the ITC registers.
ITC registers for timer interrupts
The following shows the control bits of the ITC provided for the 8-bit timer:
Interrupt flag IIFT0
∗
IIFT0
: 8-bit Timer Interrupt Flag in the Interrupt Flag (ITC_IFLG) Register (D8/0x4300)
Interrupt enable bit IIEN0
∗
IIEN0
: 8-bit Timer Interrupt Enable Bit in the Interrupt Enable (ITC_EN) Register (D8/0x4302)
Interrupt level setup bits IILV0
∗
IILV0[2:0]
: 8-bit Timer Interrupt Level Bits in the Internal Interrupt Level Setup (ITC_ILV0) Register 0
(D[2:0]/0x430e)
When an underflow occurs in the timer, the corresponding interrupt flag is set to 1.
If the interrupt enable bit corresponding to that interrupt flag has been set to 1, the ITC sends an interrupt
request to the S1C17 Core. To disable the timer interrupt, set the interrupt enable bit to 0.
The interrupt flag is always set to 1 by the timer underflow pulse, regardless of how the interrupt enable bit is
set (even when set to 0).
The interrupt level setup bits set the interrupt level (0 to 7) of the timer interrupt.
An interrupt request to the S1C17 Core is accepted only when all the conditions described below are met.
• The interrupt enable bit is set to 1.
• The IE (Interrupt Enable) bit of the PSR (Processor Status Register) in the S1C17 Core is set to 1.
• The timer interrupt has a higher interrupt level than the value that is set in the IL field of the PSR.
• No other cause of interrupt having higher priority, such as NMI, has occurred.
For details on these interrupt control registers, as well as the device operation when an interrupt has occurred,
see Chapter 6, “Interrupt Controller (ITC).”
Interrupt vector
The following shows the vector number and vector address for the timer interrupt:
Vector number: 12 (0x0c)
Vector
address:
0x8030
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 ...