70
5.2
Interrupt Sources
There are four types of interrupt sources: NMI, user break, IRQ, and on-chip supporting module
interrupts.
Interrupt rankings are expressed as priority levels (0–16), with 0 the lowest and 16 the highest. An
interrupt set to level 0 is masked.
5.2.1
NMI Interrupts
NMI is the highest-priority interrupt (level 16) and is always accepted. Input at the NMI pin is
edge-sensed. Either the rising or falling edge can be selected by setting the NMI edge select bit
(NMIE) in the interrupt control register (ICR). NMI interrupt exception handling sets the interrupt
mask level bits (I3–I0) in the status register (SR) to level 15.
5.2.2
User Break Interrupt
A user break interrupt occurs when a break condition is satisfied in the user break controller
(UBC). A user break interrupt has priority level 15. User break interrupt exception handling sets
the interrupt mask level bits (I3–I0) in the status register (SR) to level 15. For further details on the
user break interrupt, see section 6, User Break Controller (UBC).
5.2.3
IRQ Interrupts
IRQ interrupts are requested by input from pins
IRQ0
–
IRQ7
. IRQ sense select bits 0–7 (IRQ0S–
IRQ7S) in the interrupt control register (ICR) can select low-level sensing or falling-edge sensing
for each pin independently. Interrupt priority registers A and B (IPRA and IPRB) can select
priority levels from 0–15 for each pin. IRQ interrupt exception handling sets the interrupt mask
level bits (I3–I0) in the status register (SR) to the priority level value of the IRQ interrupt that was
accepted.
Summary of Contents for HD6417032
Page 21: ......
Page 35: ...xiv ...
Page 85: ...50 ...
Page 101: ...66 ...
Page 129: ...94 ...
Page 135: ...100 ...
Page 343: ...308 ...
Page 369: ...334 ...
Page 383: ...348 ...
Page 475: ...440 ...
Page 525: ...490 CK RAS CAS TRp TRc TRcc tRASD1 tRASD2 tCASD3 tCASD2 TRr tCSR Figure 20 18 Self Refresh ...
Page 578: ...543 CK RAS CAS TRp TRc TRcc tRASD1 tRASD2 tCASD3 tCASD2 TRr tCSR Figure 20 62 Self Refresh ...
Page 689: ...654 ...