REV. 0
ADSP-2186M
–9–
Interrupts
The interrupt controller allows the processor to respond to the
11 possible interrupts and reset with minimum overhead. The
ADSP-2186M provides four dedicated external interrupt input
pins: IRQ2, IRQL0, IRQL1, and IRQE (shared with the PF7:4
pins). In addition, SPORT1 may be reconfigured for IRQ0,
IRQ1, FI and FO, for a total of six external interrupts. The
ADSP-2186M also supports internal interrupts from the timer,
the byte DMA port, the two serial ports, software, and the power-
down control circuit. The interrupt levels are internally prioritized
and individually maskable (except power- down and reset). The
IRQ2, IRQ0, and IRQ1 input pins can be programmed to be
either level- or edge-sensitive. IRQL0 and IRQL1 are level-
sensitive and IRQE is edge-sensitive. The priorities and vector
addresses of all interrupts are shown in Table I.
Table I. Interrupt Priority and Interrupt Vector Addresses
Interrupt Vector
Source Of Interrupt Address (Hex)
Reset (or Power-Up with PUCR = 1) 0000 (Highest Priority)
Power-Down (Nonmaskable) 002C
IRQ2 0004
IRQL1 0008
IRQL0 000C
SPORT0 Transmit 0010
SPORT0 Receive 0014
IRQE 0018
BDMA Interrupt 001C
SPORT1 Transmit or IRQ1 0020
SPORT1 Receive or IRQ0 0024
Timer 0028 (Lowest Priority)
Interrupt routines can either be nested with higher priority inter-
rupts taking precedence or processed sequentially. Interrupts
can be masked or unmasked with the IMASK register. Individual
interrupt requests are logically ANDed with the bits in IMASK;
the highest priority unmasked interrupt is then selected. The
power-down interrupt is nonmaskable.
The ADSP-2186M masks all interrupts for one instruction
cycle following the execution of an instruction that modifies the
IMASK register. This does not affect serial port autobuffering
or DMA transfers.
The interrupt control register, ICNTL, controls interrupt nest-
ing and defines the IRQ0, IRQ1, and IRQ2 external interrupts
to be either edge- or level-sensitive. The IRQE pin is an exter-
nal edge sensitive interrupt and can be forced and cleared. The
IRQL0 and IRQL1 pins are external level sensitive interrupts.
The IFC register is a write-only register used to force and clear
interrupts. On-chip stacks preserve the processor status and are
automatically maintained during interrupt handling. The stacks
are twelve levels deep to allow interrupt, loop, and subroutine
nesting. The following instructions allow global enable or disable
servicing of the interrupts (including power down), regardless
of the state of IMASK. Disabling the interrupts does not affect
serial port autobuffering or DMA.
ENA INTS;
DIS INTS;
When the processor is reset, interrupt servicing is enabled.
LOW POWER OPERATION
The ADSP-2186M has three low power modes that significantly
reduce the power dissipation when the device operates under
standby conditions. These modes are:
• Power-Down
•Idle
• Slow Idle
The CLKOUT pin may also be disabled to reduce external
power dissipation.
Power-Down
The ADSP-2186M processor has a low power feature that lets
the processor enter a very low-power dormant state through
hardware or software control. Following is a brief list of power-
down features. Refer to the ADSP-2100 Family User’s Manual,
“System Interface” chapter, for detailed information about the
power-down feature.
• Quick recovery from power-down. The processor begins
executing instructions in as few as 200 CLKIN cycles.
• Support for an externally generated TTL or CMOS processor
clock. The external clock can continue running during power-
down without affecting the lowest power rating and 200 CLKIN
cycle recovery.
• Support for crystal operation includes disabling the oscillator
to save power (the processor automatically waits approximately
4096 CLKIN cycles for the crystal oscillator to start or stabi-
lize), and letting the oscillator run to allow 200 CLKIN cycle
start-up.
• Power-down is initiated by either the power-down pin (PWD)
or the software power-down force bit. Interrupt support allows
an unlimited number of instructions to be executed before
optionally powering down. The power-down interrupt also
can be used as a nonmaskable, edge-sensitive interrupt.
• Context clear/save control allows the processor to continue
where it left off or start with a clean context when leaving the
power-down state.
• The RESET pin also can be used to terminate power-down.
• Power-down acknowledge pin indicates when the processor
has entered power-down.
Idle
When the ADSP-2186M is in the Idle Mode, the processor
waits indefinitely in a low-power state until an interrupt occurs.
When an unmasked interrupt occurs, it is serviced; execution
then continues with the instruction following the IDLE instruc-
tion. In Idle mode IDMA, BDMA and autobuffer cycle steals
still occur.
