DSP56KFAMUM/AD(1996) View Datasheet(PDF) - Motorola => Freescale

Part Name

Description

Manufacturer

DSP56KFAMUM/AD
(Rev.:1996)

24-BIT DIGITAL SIGNAL PROCESSOR

Motorola => Freescale 

Signal/Pin Descriptions

Interrupt and Mode Control

INTERRUPT AND MODE CONTROL

Table 1-8 Interrupt and Mode Control Signals

Signal Name

Signal

Type

State

during

Reset

Signal Description

MODA/IRQA Input Input

MODB/IRQB Input Input

Mode Select A/External Interrupt Request A—This input has

two functions:

1. to select the initial chip operating mode, and

2. after synchronization, to allow an external device to

request a DSP interrupt.

MODA is read and internally latched in the DSP when the

processor exits the Reset state. MODA, MODB, and MODC

select the initial chip operating mode. Several clock cycles

(depending on PLL stabilization time) after leaving the Reset

state, the MODA signal changes to external interrupt request

IRQA. The chip operating mode can be changed by software

after reset. The IRQA input is a synchronized external

interrupt request that indicates that an external device is

requesting service. It may be programmed to be level-sensitive

or negative-edge-sensitive. If level-sensitive triggering is

selected, an external pull up resistor is required for wired-OR

operation. If the processor is in the Stop state and IRQA is

asserted, the processor will exit the Stop state.

Mode Select B/External Interrupt Request B—This input has

two functions:

1. to select the initial chip operating mode, and

2. after internal synchronization, to allow an external

device to request a DSP interrupt.

MODB is read and internally latched in the DSP when the

processor exits the Reset state. MODA, MODB, and MODC

select the initial chip operating mode. Several clock cycles

(depending on PLL stabilization time) after leaving the Reset

state, the MODB signal changes to external interrupt request

IRQB. After reset, the chip operating mode can be changed by

software. The IRQB input is an external interrupt request that

indicates that an external device is requesting service. It may

be programmed to be level-sensitive or negative-edge-

triggered. If level-sensitive triggering is selected, an external

pull up resistor is required for wired-OR operation.

1-10

DSP56002/D, Rev. 3

MOTOROLA

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