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Signal Descriptions
General Purpose Input/Output (GPIO)
2.9
GENERAL PURPOSE INPUT/OUTPUT (GPIO)
Signal
Signal Type
Name
GPIO0–
Input or
GPIO7
Output
(standard or
open-drain)
2.10
DIGITAL AUDIO INTERFACE (DAX)
Signal Name
Type
ADO
Output
ACI
Input
2-18
Table 2-10 General Purpose I/O (GPIO) Signals
State during
Reset
Disconnected
internally
Table 2-11 Digital Audio Interface (DAX) Signals
State During
Reset
Output, driven
high
Tri-stated
DSP56012 User's Manual
Signal Description
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
Signal Description
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.
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.
MOTOROLA
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