133
Table 4.9
Types of Interrupt Sources
Type
Request Source
Number of Sources
NMI
NMI signal (external input)
1
User break
User break controller
1
H-UDI
1
External interrupt*
IRQ3–IRQ0
4
IRL1–IRL15
15
On-chip peripheral module
Direct memory access controller (DMAC)
1
× 4 channels
Serial I/O (SIO)
4
× 3 channels
Serial communications interface (SCI)
4
× 2 channels
Free running timer (FRT)
4
× 3 channels
Bus state controller (BSC)
1
Note:
The SH7410 processor has two external interrupt modes. The IRQ mode uses the four
external interrupt signals IRQ3–IRQ0 as individual interrupt sources (table 4.4). The IRL
mode uses the same four pins to externally set vector numbers for the IRL1 to IRL15
interrupts (table 4.5). See section 5.2.4, External Interrupts.
4.4.2
Interrupt Priorities
The interrupt priorities are predetermined. When multiple interrupts occur simultaneously
(overlap), the interrupt controller (INTC) determines their relative priorities and begins processing
accordingly.
The priorities of interrupts are expressed using priorities 0–16, with priority 0 representing the
lowest and priority 16 the highest. The NMI interrupt has priority 16 and cannot be masked, so it
is always accepted. The user break interrupt priority is 15. The H-UDI interrupt also has priority
15.
The external interrupts have two priority modes. In one mode, four interrupt inputs (the IRQ0 to
IRQ3 signals) are used as individual external interrupt sources. Each interrupt source can set its
interrupt priority using the interrupt priority register A (IPRA) in the interrupt controller (INTC).
In the second mode, the four interrupt signals specify the interrupt priorities, 1–15.
On-chip peripheral module interrupt priorities can be set freely using the interrupt priority
registers B–D (IPRB–IPRD) in the INTC, as listed in table 4.10.
Only priorities 0–15 can be set for external interrupts or on-chip peripheral module interrupts.
Level 16 cannot be set. For more information on IPRA–IPRD, see section 5.3.1, Interrupt Priority
Registers A–D (IPRA–IPRD).