12 8-BIT TIMER (T8F)
S1C17001 TECHNICAL MANUAL
EPSON
133
12.9 8-bit Timer Interrupts
The 8-bit timer outputs interrupt requests to the interrupt controller (ITC) when the counter underflows.
To generate a timer underflow interrupt, the interrupt level and interrupt permission should be set using the ITC
registers.
Timer interrupt ITC register
The 8-bit timer ITC control bits are listed below.
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 setting bit IILV0
∗
IILV0[2:0]
: 8-bit Timer Interrupt Level Bits in the Internal Interrupt Level Setup (ITC_ILV0) Register 0
(D[2:0]/0x430e)
If an underflow occurs in the timer, the corresponding interrupt flag is set to 1.
If the interrupt enable bit corresponding to that interrupt flag is set to 1, the ITC sends an interrupt request to
the S1C17 core. To prohibit timer interrupts, set the interrupt enable bit to 0 beforehand. The interrupt flag will
be set to 1 by the timer underflow pulse regardless of the interrupt enable bit setting (i.e., even if set to 0).
The interrupt level setting bit sets the timer interrupt level (0 to 7).
The S1C17 core accepts interrupts when all of the following conditions are satisfied:
• The interrupt enable bit has been set to 1.
• The PSR (S1C17 core internal processor status register) IE (interrupt enable) bit has been set to 1.
• The timer interrupt has a higher interrupt level set than that set for the PSR IL (interrupt level).
• No other interrupt factors having higher precedence (e.g., NMI) are present.
For more information on these interrupt control registers and operations when interrupts occur, see “6 Interrupt
Controller (ITC).”
Interrupt vectors
The 8-bit timer interrupt vector numbers and vector addresses are listed below.
Vector number: 12 (0x0c)
Vector
address:
0x8030
Summary of Contents for S1C17001
Page 1: ...Technical Manual S1C17001 CMOS 16 BIT SINGLE CHIP MICROCONTROLLER ...
Page 33: ...4 POWER SUPPLY VOLTAGE 24 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 63: ...6 INITERRUPT CONTROLLER 54 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 87: ...8 CLOCK GENERATOR CLG 78 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 91: ...9 PRESCALER PSC 82 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 133: ...11 16 BIT TIMER T16 124 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 211: ...16 STOPWATCH TIMER SWT 202 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 219: ...17 WATCHDOG TIMER WDT 210 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 241: ...18 UART 232 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
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