2-18 DSP56012 User’s Manual MOTOROLA

Signal Descriptions

General Purpose Input/Output (GPIO)

2.9 GENERAL PURPOSE INPUT/OUTPUT (GPIO)

2.10 DIGITAL AUDIO INTERFACE (DAX)

Table 2-10 General Purpose I/O (GPIO) Signals

Signal
Name Signal Type State during
Reset Signal Description
GPIO0–
GPIO7 Input or
Output
(standard or
open-drain)
Disconnected
internally General Purpose Input/Output—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

Table 2-11 Digital Audio Interface (DAX) Signals

Signal Name Type State During
Reset Signal Description
ADO Output Output, driven
high Digital Audio Data Output—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 Audio Clock Input—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.