ADSP-21992(RevPrA) Ver la hoja de datos (PDF) - Analog Devices
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ADSP-21992 Datasheet PDF : 48 Pages
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PRELIMINARY TECHNICAL DATA
August 2002
For current information contact Analog Devices at (781) 937-1799
ADSP-21992
signal can be programmed to set the FLAG on either a level
(level sensitive input/interrupt) or an edge (edge sensitive
input/interrupt).
The FIO module can also be used to generate an asynchro-
nous unregistered wake up signal FIO_WAKEUP for DSP
core wake up after power down.
The FIO Lines, PF7 - PF1 can also be configured as external
slave select outputs for the SPI Communications Port, while
PF0 can be configured to act as a Slave select input.
The FIO Lines can be configured to act as a PWM shutdown
source for the three phase PWM generation unit of the
ADSP-21992.
Watchdog Timer
The ADSP-21992 integrates a watchdog timer that can be
used as a protection mechanism against unintentional
software events. It can be used to cause a complete DSP and
peripheral reset in such an event. The watchdog timer
consists of a 16-bit timer that is clocked at the external clock
rate (CLKIN or crystal input frequency).
In order to prevent an unwanted timeout or reset, it is
necessary to periodically write to the watchdog timer
register. During abnormal system operation, the watchdog
count will eventually decrement to 0 and a watchdog
timeout will occur. In the system, the watchdog timeout will
cause a full reset of the DSP core and peripherals.
General Purpose Timers
The ADSP-21992 contains a general purpose timer unit
that contains three identical 32-bit timers. The three pro-
grammable interval timers (Timer0, Timer1 and Timer2)
generate periodic interrupts. Each timer can be indepen-
dently set to operate in one of three modes:
• Pulse Waveform Generation (PWM_OUT) mode
• Pulse Width Count/Capture (WDTH_CAP) mode
• External Event Watchdog (EXT_CLK) mode
Each Timer has one bidirectional chip pin, TMR2-TMR0.
For each timer, the associated pin is configured as an output
pin in PWM_OUT Mode and as input pin in WDTH_CAP
and EXT_CLK Modes.
Interrupts
The interrupt controller lets the DSP respond to 17 inter-
rupts with minimum overhead. The DSP core implements
an interrupt priority scheme as shown in Table 2. Applica-
tions can use the unassigned slots for software and
peripheral interrupts. The Peripheral Interrupt Controller
is used to assign the various peripheral interrupts to the 12
user assignable interrupts of the DSP core.
Table 2. Interrupt Priorities/Addresses
Interrupt
Emulator (NMI)
—Highest Priority
Reset (NMI)
Power Down (NMI)
Loop and PC Stack
Emulation Kernel
User Assigned Interrupt
(USR0)
User Assigned Interrupt
(USR1)
User Assigned Interrupt
(USR2)
User Assigned Interrupt
(USR3)
User Assigned Interrupt
(USR4)
User Assigned Interrupt
(USR5)
User Assigned Interrupt
(USR6)
User Assigned Interrupt
(USR7)
User Assigned Interrupt
(USR8)
User Assigned Interrupt
(USR9)
User Assigned Interrupt
(USR10)
User Assigned Interrupt
(USR11)
—Lowest Priority
IMASK/
IRPTL
NA
Vector Address
NA
0
0x00 0000
1
0x00 0020
2
0x00 0040
3
0x00 0060
4
0x00 0080
5
0x00 00A0
6
0x00 00C0
7
0x00 00E0
8
0x00 0100
9
0x00 0120
10
0x00 0140
11
0x00 0160
12
0x00 0180
13
0x00 01A0
14
0x00 01C0
15
0x00 01E0
There is no assigned priority for the peripheral interrupts
after reset. To assign the peripheral interrupts a different
priority, applications write the new priority to their corre-
sponding control bits (determined by their ID) in the
Interrupt Priority Control register.
Interrupt routines can either be nested with higher priority
interrupts 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 emulation, power down, and
reset interrupts are nonmaskable with the IMASK register,
but software can use the DIS INT instruction to mask the
power down interrupt.
REV. PrA This information applies to a product under development Its characteristics and specifications are subject to change without notice Analog
11
Devices assumes no obligation regarding future manufacturing unless otherwise agreed to in writing
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