Datasheet

ADSP-21483/ADSP-21486/ADSP-21487/ADSP-21488/ADSP-21489
Rev. B | Page 11 of 68 | March 2013
Delay Line DMA
The processor provides delay line DMA functionality. This
allows processor reads and writes to external delay line buffers
(and hence to external memory) with limited core interaction.
Scatter/Gather DMA
The processor provides scatter/gather DMA functionality. This
allows processor DMA reads/writes to/from non contiguous
memory blocks.
FFT Accelerator
The FFT accelerator implements a radix-2 complex/real input,
complex output FFT with no core intervention. The FFT accel-
erator runs at the peripheral clock frequency.
FIR Accelerator
The FIR (finite impulse response) accelerator consists of a 1024
word coefficient memory, a 1024 word deep delay line for the
data, and four MAC units. A controller manages the accelerator.
The FIR accelerator runs at the peripheral clock frequency.
IIR Accelerator
The IIR (infinite impulse response) accelerator consists of a
1440 word coefficient memory for storage of biquad coeffi-
cients, a data memory for storing the intermediate data, and one
MAC unit. A controller manages the accelerator. The IIR accel-
erator runs at the peripheral clock frequency.
Watchdog Timer
The watchdog timer is used to supervise the stability of the sys-
tem software. When used in this way, software reloads the
watchdog timer in a regular manner so that the downward
counting timer never expires. An expiring timer then indicates
that system software might be out of control.
The 32-bit watchdog timer that can be used to implement a soft-
ware watchdog function. A software watchdog can improve
system reliability by forcing the processor to a known state
through generation of a system reset, if the timer expires before
being reloaded by software. Software initializes the count value
of the timer, and then enables the timer. The watchdog timer
resets both the core and the internal peripherals. Note that this
feature is available on the 176-lead package only.
SYSTEM DESIGN
The following sections provide an introduction to system design
options and power supply issues.
Program Booting
The internal memory of the ADSP-2148x boots at system
power-up from an 8-bit EPROM via the external port, an SPI
master, or an SPI slave. Booting is determined by the boot con-
figuration (BOOT_CFG2–0) pins in Table 9 for the 176-lead
package and Table 10 for the 100-lead package.
The “Running Reset” feature allows a user to perform a reset of
the processor core and peripherals, but without resetting the
PLL and SDRAM controller, or performing a boot. The
functionality of the RESETOUT
/RUNRSTIN pin has now been
extended to also act as the input for initiating a Running Reset.
For more information, see the ADSP-214xx SHARC Processor
Hardware Reference.
Power Supplies
The processors have separate power supply connections for the
internal (V
DD_INT
) and external (V
DD_EXT
) power supplies. The
internal supply must meet the V
DD_INT
specifications. The
external supply must meet the V
DD_EXT
specification. All exter-
nal supply pins must be connected to the same power supply.
To reduce noise coupling, the PCB should use a parallel pair of
power and ground planes for V
DD_INT
and GND.
Static Voltage Scaling (SVS)
Some models of the ADSP-2148x feature Static Voltage Scaling
(SVS) on the V
DD_INT
power supply. (See the Ordering Guide
on Page 66 for model details.) This voltage specification tech-
nique can provide significant performance benefits including
450 MHz core frequency operation without a significant
increase in power.
SVS optimizes the required V
DD_INT
voltage for each individual
device to enable enhanced operating frequency up to 450 MHz.
The optimized SVS voltage results in a reduction of maximum
I
DD_INT
which enables 450 MHz operation at the same or lower
maximum power than 400 MHz operation at a fixed voltage
supply. Implementation of SVS requires a specific voltage regu-
lator circuit design and initialization code.
Refer to the Engineer-to-Engineer Note “Static Voltage Scaling
for ADSP-2148x Processors” (EE-357) for further information.
The EE-Note details the requirements and process to implement
a SVS power supply system to enable operation up to 450 MHz.
This applies only to specific products within the ADSP-2148x
family which are capable of supporting 450 MHz operation.
Table 9. Boot Mode Selection, 176-Lead Package
BOOT_CFG2–0 Booting Mode
000 SPI Slave Boot
001 SPI Master Boot
010 AMI User Boot (for 8-bit Flash Boot)
011 No boot (processor executes from internal
ROM after reset)
1xx Reserved
Table 10. Boot Mode Selection, 100-Lead Package
BOOT_CFG1–0 Booting Mode
00 SPI Slave Boot
01 SPI Master Boot
10 Reserved
11 No boot (processor executes from internal
ROM after reset)