ADSP-21MOD980N-000 Просмотр технического описания (PDF) - Analog Devices

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ADSP-21MOD980N-000

MultiPort Internet Gateway Processor

Analog Devices 

PRELIMINARY TECHNICAL DATA

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ADSP-21mod980N

Table 2. Host Pins (Mode C = 1) Modem Processors 1-8

Pin Name

# of

Pins

Input/

Output

Function

IAD[15:0] 321 I/O

IDMA Port

Address/Data Bus

A0

1

O

Address Pin for Exter-

nal I/O, Program,

Data, or Byte access

D[23:8]

IWR

IRD

IAL

16 I/O

21

I

21

I

21

I

Data I/O Pins for Pro-

gram, Data Byte and

I/O spaces

IDMA Write Enable

IDMA Read Enable

IDMA Address Latch

Pin

IS

8

I

IDMA Selects

IACK

21

O

IDMA Port Acknowl-

edge Configurable in

Mode D; Open Drain

1 There are two distinct IAD buses. One addresses DSPs 1-4 and the other

communicates with DSPs 5-8. See Figure 2 for details.

INTERRUPTS

The interrupt controller allows each modem processor in

the modem pool to respond individually to eleven possible

interrupts and RESET with minimum overhead. The

ADSP-21mod980N provides four dedicated external inter-

rupt input pins, IRQ2, IRQL1, IRQL0, and IRQE (shared

with the PF[7:4] pins) for each modem processor. The

ADSP-21mod980N also supports internal interrupts from

the timer, the byte DMA port, the serial port, software, and

the power-down control circuit. The interrupt levels are

internally prioritized and individually maskable (except

power down and RESET). The IRQ2, IRQ1, and IRQ0

input pins can be programmed to be either level- or

edge-sensitive. IRQL0 and IRQL1 are level-sensitive and

IRQE is edge sensitive. The priorities and vector addresses

of all interrupts are shown in Table on page 7. When the

modem pool is reset, interrupt servicing is disabled.

Table 3. Interrupt Priority and Interrupt Vector

Addresses

Source Of Interrupt

Interrupt Vector Address

(Hex)

RESET (or Power-Up

with PUCR = 1)

Power Down

(Nonmaskable)

IRQ2

IRQL1

IRQL0

SPORT0 Transmit

SPORT0 Receive

IRQE

BDMA Interrupt

SPORT1 Transmit or

IRQ1

SPORT1 Receive or

IRQ0

Timer

0x0000 (Highest Priority)

0x002C

0x0004

0x0008

0x000C

0x0010

0x0014

0x0018

0x001C

0x0020

0x0024

0x0028 (Lowest Priority)

LOW POWER OPERATION

The ADSP-21mod980N has three low power modes that

significantly reduce the power dissipation when the device

operates under standby conditions. These modes are:

• Power Down

• Idle

• Slow Idle

The CLKOUT pin may also be disabled to reduce external

power dissipation.

POWER DOWN

The ADSP-21mod980N modem pool has a low power fea-

ture that lets the modem pool enter a very low power

dormant state through software control. Here is a brief list

REV. PrB 6/2001

7

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