DSP56374 View Datasheet(PDF) - Motorola => Freescale

Part Name

Description

Manufacturer

DSP56374

24-Bit Audio Digital Signal Processor

Motorola => Freescale 

Signal Groupings

Table 9. Serial Host Interface Signals (Continued)

Signal

Name

Signal Type

State during

Reset

Signal Description

HREQ Input or Output

Tri-stated

Host Request—This signal is an active low Schmitt-trigger input when

configured for the master mode but an active low output when configured

for the slave mode.

When configured for the slave mode, HREQ is asserted to indicate that the

SHI is ready for the next data word transfer and de-asserted at the first

clock pulse of the new data word transfer. When configured for the master

mode, HREQ is an input. When asserted by the external slave device, it will

trigger the start of the data word transfer by the master. After finishing the

data word transfer, the master will await the next assertion of HREQ to

proceed to the next transfer. This pin can also be programmed as GPIO.

Port H4—When HREQ is configured as GPIO, this signal is individually

programmable as input, output, or internally disconnected.

Input, output,

PH4

or

disconnected

This pin has an internal pull up resistor.

This input is 5 V tolerant.

3.7 Enhanced Serial Audio Interface

Table 10. Enhanced Serial Audio Interface Signals

Signal Name Signal Type

HCKR

Input or output

PC2

Input, output, or

disconnected

State during

Reset

Signal Description

GPIO

disconnected

High Frequency Clock for Receiver—When programmed

as an input, this signal provides a high frequency clock

source for the ESAI receiver as an alternate to the DSP

core clock. When programmed as an output, this signal

can serve as a high-frequency sample clock (e.g., for

external digital to analog converters [DACs]) or as an

additional system clock.

Port C2—When the ESAI is configured as GPIO, this

signal is individually programmable as input, output, or

internally disconnected.

The default state after reset is GPIO disconnected.

This pin has an internal pull up resistor.

This input is 5 V tolerant.

10

PRELIMINARY

Freescale Semiconductor

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