參數(shù)資料
型號: ADSP-21XX
廠商: Analog Devices, Inc.
英文描述: ADSP-2100 Family DSP Microcomputers
中文描述: 的ADSP - 2100系列DSP的微機
文件頁數(shù): 7/32頁
文件大?。?/td> 231K
代理商: ADSP-21XX
ADSP-21mod870
–7–
REV. 0
ratio. The default form of the instruction, when no clock divisor
is given, is the standard IDLE instruction.
When the IDLE (
n
) instruction is used, it effectively slows down
the processor’s internal clock and thus its response time to in-
coming interrupts. The one-cycle response time of the standard
idle state is increased by n, the clock divisor. When an enabled
interrupt is received, the ADSP-21mod870 will remain in the idle
state for up to a maximum of
n
processor cycles (
n
= 16, 32, 64,
or 128) before resuming normal operation.
When the IDLE (
n
) instruction is used in systems that have an
externally generated serial clock (SCLK), the serial clock rate
may be faster than the processor’s reduced internal clock rate.
Under these conditions, interrupts must not be generated at a
faster rate than can be serviced, due to the additional time the
processor takes to come out of the idle state (a maximum of
n
processor cycles).
SYSTEM INTERFACE
Figure 3 shows a typical multichannel modem configuration
with the ADSP-21mod870. A line interface can be used to
connect the multichannel subscriber or client data stream to the
multichannel serial port of the ADSP-21mod870. The ADSP-
21mod870 can support 24 or 32 channels. The IDMA port of
the ADSP-21mod870 is used to give a host processor full access
to the internal memory of the ADSP-21mod870. This lets the
host dynamically configure the ADSP-21mod870 by loading code
and data into its internal memory. This configuration also lets
the host access server data directly from the ADSP-21mod870’s
internal memory. In this configuration, the ADSP-21mod870
should be put into host memory mode where Mode C = 1,
Mode B = 0 and Mode A = 1 (see Table II).
CLOCK SIGNALS
The ADSP-21mod870 can be clocked by either a crystal or a
TTL-compatible clock signal.
The CLKIN input cannot be halted, changed during operation,
or operated below the specified frequency during normal opera-
tion. The only exception is while the processor is in the power-
down state. For additional information, refer to Chapter 9,
ADSP-2100 Family User’s Manual,
Third Edition,
for detailed
information on this power-down feature.
If an external clock is used, it should be a TTL-compatible
signal running at half the instruction rate. The signal is con-
nected to the processor’s CLKIN input. When an external clock
is used, the XTAL input must be left unconnected.
The ADSP-21mod870 uses an input clock with a frequency
equal to half the instruction rate; a 26 MHz input clock yields a
19 ns processor cycle (which is equivalent to 52 MHz). Nor-
mally, instructions are executed in a single processor cycle. All
device timing is relative to the internal instruction clock rate,
which is indicated by the CLKOUT signal when enabled.
Because the ADSP-21mod870 includes an on-chip oscillator
circuit, an external crystal may be used. The crystal should be
connected across the CLKIN and XTAL pins, with two capaci-
tors connected as shown in Figure 4. Capacitor values are de-
pendent on crystal type and should be specified by the crystal
manufacturer. A parallel-resonant, fundamental frequency,
microprocessor-grade crystal should be used.
A clock output (CLKOUT) signal is generated by the processor
at the processor’s cycle rate. This is enabled and disabled by the
CLKODIS bit in the SPORT0 Autobuffer Control Register.
ADSP-
21mod870
IDMA
SP0
ADSP-
21mod870
SP0
IDMA
ADSP-
21mod870
IDMA
SP0
ADSP-
21mod870
SP0
IDMA
ADSP-
21mod870
IDMA
SP0
ADSP-
21mod870
SP0
IDMA
ADSP-
21mod870
IDMA
SP0
ADSP-
21mod870
SP0
IDMA
LINE
INTERFACE
CALL
CONTROL
T1, E1, PRI,
xDSL, ATM
HOST BUS
HOST
(2183)
LAN OR
INTERNET
ADSP-21mod870 FUNCTIONS
HOST FUNCTIONS
MULTI-DSP CONTROL AND OVERLAY
MANAGEMENT
SERVICE 32 DSPs/HOST
DATA PACKETIZING
V.34/56k MODEM
V.17 FAX
V.42, V.42bis, MNP2-5
DTMF DIALING
CALLER ID
HDLC PROTOCOL
Figure 3. Network Access System
CLKIN
CLKOUT
XTAL
DSP
Figure 4. External Crystal Connections
相關(guān)PDF資料
PDF描述
ADSP-21MOD970-110 Multiport Internet Gateway Processor Solution
ADSP-21mod970-110 Data Pump Solution Gateway Processor Solution(多端口網(wǎng)關(guān)處理器解決方案)
ADSP-21MOD980N MultiPort Internet Gateway Processor
ADSP-21MOD980N-000 CAP 27PF 100V 10% X7R AXIAL BULK M-MIL-PRF-39014
ADSP-21MSP58BST-104 DSP Microcomputers
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ADSP-3128AJG 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Analog Devices 功能描述:
ADSP-3128ASG/883B 制造商:Rochester Electronics LLC 功能描述:- Bulk
ADSP-3201JG 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Analog Devices 功能描述:
ADSP-3201KG 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Analog Devices 功能描述:MULTIPLIER, 144 Pin, Ceramic, PGA
ADSP-3201TG 制造商:Rochester Electronics LLC 功能描述:- Bulk