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參數資料
| 型號： | ADSP-21990 |
| 廠商： | Analog Devices, Inc. |
| 元件分類： | 數字信號處理 |
| 英文描述： | 16-bit fixed point DSP with Flash |
| 中文描述： | 具有閃存的 16 位定點 DSP |
| 文件頁數： | 12/44頁 |
| 文件大小： | 574K |
| 代理商： | ADSP-21990 |
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ADSP-21990
–12–
REV. 0
Power-Down All Mode
When the ADSP-21990 is in Power-Down All mode, the DSP
core clock, the peripheral clock, and the PLL are all stopped. The
DSP does not retain the contents of the instruction pipeline. The
peripheral bus is stopped, so the peripherals cannot receive data.
To exit Power-Down Core/Peripherals mode, the DSP responds
to an interrupt and (after 500 cycles to re-stabilize the PLL)
resumes executing instructions.
Clock Signals
The ADSP-21990 can be clocked by a crystal oscillator or a
buffered, shaped clock derived from an external clock oscillator.
If a crystal oscillator is used, the crystal should be connected
across the CLKIN and XTAL pins, with two capacitors
connected as shown in
Figure 5
. Capacitor values are dependent
on crystal type and should be specified by the crystal manufac-
turer. A parallel resonant, fundamental frequency,
microprocessor grade crystal should be used for this
configuration.
If a buffered, shaped clock is used, this external clock connects
to the DSP CLKIN pin. CLKIN input cannot be halted,
changed, or operated below the specified frequency during
normal operation. This clock signal should be a TTL compatible
signal. When an external clock is used, the XTAL input must be
left unconnected.
The DSP provides a user programmable 1 to 32 multiplica-
tion of the input clock, including some fractional values, to
support 128 external to internal (DSP core) clock ratios. The
BYPASS pin, and MSEL6–0 and DF bits, in the PLL configu-
ration register, decide the PLL multiplication factor at reset. At
run time, the multiplication factor can be controlled in software.
To support input clocks greater that 100 MHz, the PLL uses an
additional bit (DF). If the input clock is greater than 100 MHz,
DF must be set. If the input clock is less than 100 MHz, DF must
be cleared. For clock multiplier settings, see the
ADSP-2199x
Mixed Signal DSP Controller Hardware Reference
.
The peripheral clock is supplied to the CLKOUT pin.
All on-chip peripherals for the ADSP-21990 operate at the rate
set by the peripheral clock. The peripheral clock (HCLK) is
either equal to the core clock rate or one half the DSP core clock
rate (CCLK). This selection is controlled by the IOSEL bit in
the PLLCTL register. The maximum core clock is 160 MHz
for the ADSP-21990BST and 150 MHz for the ADSP-
21990BBC.The maximum peripheral clock is 80 MHz for the
ADSP-21990BST and 75 MHz for the ADSP-21990BBC—the
combination of the input clock and core/peripheral clock ratios
may not exceed these limits.
Reset and Power-On Reset (POR)
The
RESET
pin initiates a complete hardware reset of the ADSP-
21990 when pulled low. The
RESET
signal must be asserted
when the device is powered up to assure proper initialization. The
ADSP-21990 contains an integrated power-on reset (POR)
circuit that provides an output reset signal,
POR
, from the ADSP-
21990 on power-up and if the power supply voltage falls below
the threshold level. The ADSP-21990 may be reset from an
external source using the
RESET
signal, or alternatively, the
internal power-on reset circuit may be used by connecting the
POR
pin to the
RESET
pin. During power-up the
RESET
line
must be activated for long enough to allow the DSP core’s internal
clock to stabilize. The power-up sequence is defined as the total
time required for the crystal oscillator to stabilize after a valid
VDD is applied to the processor and for the internal phase-locked
loop (PLL) to lock onto the specific crystal frequency. A
minimum of 512 cycles will ensure that the PLL has locked (this
does not include the crystal oscillator start-up time).
The
RESET
input contains some hysteresis. If an RC circuit is
used to generate the
RESET
signal, the circuit should use an
external Schmitt trigger.
The master reset sets all internal stack pointers to the empty stack
condition, masks all interrupts, and resets all registers to their
default values (where applicable). When
RESET
is released, if
there is no pending bus request, program control jumps to the
location of the on-chip boot ROM (0xFF0000) and the booting
sequence is performed.
Power Supplies
The ADSP-21990 has separate power supply connections for the
internal (V
DDINT
) and external (V
DDEXT
) power supplies. The
internal supply must meet the 2.5 V requirement. The external
supply must be connected to a 3.3 V supply. All external supply
pins must be connected to the same supply. The ideal power-on
sequence for the DSP is to provide power-up of all supplies simul-
taneously. If there is going to be some delay in power-up between
the supplies, provide V
DD
first, then V
DD_IO
.
Figure 5. External Crystal Connections
CLKIN
XTAL
ADSP-2199x
相關PDF資料 |
PDF描述 |
|---|---|
| ADSP-21990BBC | 16-bit fixed point DSP with Flash |
| ADSP-21990BST | 16-bit fixed point DSP with Flash |
| ADSP-21MOD870-100 | Single Chip Digital Modem(單片數字調制解調器) |
| ADSP-21MOD870-110 | Internet Gateway Processor Software |
| ADSP-21MOD870 | Internet Gateway Processor |
相關代理商/技術參數 |
參數描述 |
|---|---|
| ADSP-21990BBC | 制造商:Analog Devices 功能描述:DSP Fixed-Point 16-Bit 150MHz 150MIPS 196-Pin Mini-BGA 制造商:Rochester Electronics LLC 功能描述:160 MIPS, MIXED SIGNAL DSPWITH 14-BIT - Bulk |
| ADSP-21990BST | 制造商:Rochester Electronics LLC 功能描述:160 MIPS,MIXED SIGNAL DSP WITH 14BIT - Tape and Reel |
| ADSP-21990BSTZ | 功能描述:IC DSP CONTROLLER 16BIT 176-LQFP RoHS:是 類別:集成電路 (IC) >> 嵌入式 - DSP（數字式信號處理器） 系列:ADSP-21xx 標準包裝:2 系列:StarCore 類型:SC140 內核 接口:DSI，以太網，RS-232 時鐘速率:400MHz 非易失內存:外部 芯片上RAM:1.436MB 電壓 - 輸入/輸出:3.30V 電壓 - 核心:1.20V 工作溫度:-40°C ~ 105°C 安裝類型:表面貼裝 封裝/外殼:431-BFBGA，FCBGA 供應商設備封裝:431-FCPBGA（20x20） 包裝:托盤 |
| ADSP-21991BBC | 制造商:Analog Devices 功能描述:DSP Fixed-Point 16-Bit 150MHz 150MIPS 196-Pin Mini-BGA |
| ADSP-21991BBCZ | 功能描述:IC DSP CTLR 16BIT 196CSPBGA RoHS:是 類別:集成電路 (IC) >> 嵌入式 - DSP（數字式信號處理器） 系列:ADSP-21xx 標準包裝:2 系列:StarCore 類型:SC140 內核 接口:DSI，以太網，RS-232 時鐘速率:400MHz 非易失內存:外部 芯片上RAM:1.436MB 電壓 - 輸入/輸出:3.30V 電壓 - 核心:1.20V 工作溫度:-40°C ~ 105°C 安裝類型:表面貼裝 封裝/外殼:431-BFBGA，FCBGA 供應商設備封裝:431-FCPBGA（20x20） 包裝:托盤 |
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