Motorola DSP56012 Benutzerhandbuch

General Purpose I/O (GPIO) Signals

GPIO0–
GPIO7

Input or 
Output 
(standard or 
open-drain)

Disconnected 
internally

—These signals 

are used for control and handshake functions 
between the DSP and external circuitry. Each 
GPIO signal may be individually programmed to 
be one of four states: 

•

Not connected

•

Input

•

Standard output

•

Open-drain output

Digital Audio Interface (DAX) Signals

ADO

Output

Output, driven 
high

This signal is an 

audio and non-audio output in the form of 
AES/EBU, CP340 and IEC958 data in a biphase 
mark format. The signal is driven high when the 
DAX is disabled, and during hardware or software 
reset.

ACI

Input

Tri-stated

This is the DAX clock input. 

When programmed to use an external clock, this 
input supplies the DAX clock. The external clock 
frequency must 256, 384, or 512 times the audio 
sampling frequency (256 x Fs, 384 x Fs or 512 x Fs, 
respectively). The ACI signal is high impedance 
(tri-stated) only during hardware or software reset. 
If the DAX is not used, connect the ACI signal to 
ground through an external pull-down resistor to 
ensure a stable logic level at the input.