Renesas H8S/2318 series, Hardware Manual

Page: 156 / 1121

Rev. 5.00, 12/03, page 126 of 1088
8-Level Control: In interrupt control mode 2, 8-level mask level determination is performed for
the selected interrupts in interrupt acceptance control according to the interrupt priority level
(IPR).
The interrupt source selected is the interrupt with the highest priority level, and whose priority
level set in IPR is higher than the mask level.
Table 5-7 Interrupts Selected in Each Interrupt Control Mode (2)
Interrupt Control Mode Selected Interrupts
0 All interrupts
2 Highest-priority-level (IPR) interrupt whose priority level is greater
than the mask level (IPR > I2 to I0)
Default Priority Determination: When an interrupt is selected by 8-level control, its priority is
determined and a vector number is generated.
If the same value is set for IPR, acceptance of multiple interrupts is enabled, and so only the
interrupt source with the highest priority according to the preset default priorities is selected and
has a vector number generated.
Interrupt sources with a lower priority than the accepted interrupt source are held pending.
Table 5-8 shows operations and control signal functions in each interrupt control mode.
Table 5-8 Operations and Control Signal Functions in Each Interrupt Control Mode
Setting
Interrupt
Acceptance
Control
8-Level Control
Interrupt
Control
Mode
INTM1 INTM0 I I2 to I0 IPR
Default Priority
Determination T
(Trace)
0 0 0 IM X — —
*
2
—
2 1 0 X —
*
1
IM PR T
Legend:
: Interrupt operation control performed
X : No operation (All interrupts enabled)
IM : Used as interrupt mask bit
PR : Sets priority
— : Not used
Notes: 1. Set to 1 when interrupt is accepted.
2. Keep the initial setting.