adsp-2186n Analog Devices, Inc., adsp-2186n Datasheet - Page 6

• Manufacturer Part Number: adsp-2186n
• Description: Dsp Microcomputer
• Manufacturer: Analog Devices, Inc.

ADSP-218xN
Table 3. Interrupt Priority and Interrupt Vector Addresses
Interrupt routines can either be nested with higher priority
interrupts taking precedence or processed sequentially. Inter-
rupts 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.
ADSP-218xN series members mask 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 external
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 12 levels deep to allow interrupt, loop, and subroutine nest-
ing. The following instructions allow global enable or disable
servicing of the interrupts (including power-down), regardless
of the state of IMASK:
ENA INTS;
DIS INTS;
Disabling the interrupts does not affect serial port autobuffering
or DMA. When the processor is reset, interrupt servicing
is enabled.
LOW-POWER OPERATION
ADSP-218xN series members have three low-power modes that
significantly reduce the power dissipation when the device oper-
ates under standby conditions. These modes are:
Source Of Interrupt
Reset (or Power-Up with PUCR = 1) 0x0000 (Highest Priority)
Power-Down (Nonmaskable)
IRQ2
IRQL1
IRQL0
SPORT0 Transmit
SPORT0 Receive
IRQE
BDMA Interrupt
SPORT1 Transmit or IRQ1
SPORT1 Receive or IRQ0
Timer
• Power-Down
• Idle
• Slow Idle
Interrupt Vector Address
(Hex)
0x002C
0x0004
0x0008
0x000C
0x0010
0x0014
0x0018
0x001C
0x0020
0x0024
0x0028 (Lowest Priority)
Rev. A | Page 6 of 48 | August 2006
The CLKOUT pin may also be disabled to reduce external
power dissipation.
Power-Down
ADSP-218xN series members have 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-218x DSP Hardware Refer-
ence, “System Interface” chapter, for detailed information about
the power-down feature.
Idle
When the ADSP-218xN 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.
Slow Idle
The IDLE instruction is enhanced on ADSP-218xN series mem-
bers to let the processor’s internal clock signal be slowed, further
reducing power consumption. The reduced clock frequency, a
programmable fraction of the normal clock rate, is specified by a
selectable divisor given in the IDLE instruction.
The format of the instruction is:
IDLE (n);
where n = 16, 32, 64, or 128. This instruction keeps the proces-
sor fully functional, but operating at the slower clock rate. While
it is in this state, the processor’s other internal clock signals,
• Quick recovery from power-down. The processor begins
• Support for an externally generated TTL or CMOS proces-
• Support for crystal operation includes disabling the oscilla-
• Power-down is initiated by either the power-down pin
• Context clear/save control allows the processor to continue
• The RESET pin also can be used to terminate power-down.
• Power-down acknowledge pin (PWDACK) indicates when
executing instructions in as few as 200 CLKIN cycles.
sor clock. The external clock can continue running during
power-down without affecting the lowest power rating and
200 CLKIN cycle recovery.
tor to save power (the processor automatically waits
approximately 4096 CLKIN cycles for the crystal oscillator
to start or stabilize), and letting the oscillator run to allow
200 CLKIN cycle start-up.
(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.
where it left off or start with a clean context when leaving
the power-down state.
the processor has entered power-down.