Chapter 22 Multichannel Audio Serial Port (McASP).pdf

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22.3.5.4 Clocking Examples
Some examples of processes using the McASP clocking and frame flexibility are:
• Receive data from a DVD at 48 kHz, but output up-sampled or decoded audio at 96 kHz or 192 kHz.
This could be accomplished by inputting a high-frequency master clock (for example,
512 × receive FS), receiving with an internally-generated bit clock ratio of divide-by-8, and transmitting
with an internally-generated bit clock ratio of divide-by-4 or divide-by-2.
• Transmit/receive data based on one sample rate (for example, 44.1 kHz), and transmit/receive data at
a different sample rate (for example, 48 kHz).
22.3.6 Signal Descriptions
The signals used on the McASP audio interface are listed in Table 22-6.
Table 22-6. McASP Interface Signals
Device Reset
Pin I/O/Z (RESET = 0) Description
22.3.7 Pin Multiplexing
Transmitter Control
AHCLKX I/O/Z Input Transmit high-frequency master clock
AFSX I/O/Z Input Transmit frame sync or left/right clock (LRCLK)
ACLKX I/O/Z Input Transmit bit clock
Receiver Control
AHCLKR I/O/Z Input Receive high-frequency master clock
AFSR I/O/Z Input Receive frame sync or left/right clock (LRCLK)
ACLKR I/O/Z Input Receive bit clock
Mute
AMUTE I/O/Z Input Mute output
AMUTEIN I/O/Z Input Mute input
Data
AXRn I/O/Z Input TX/RX data pins
The McASP signals share pins with other processor functions. For detailed information on the McASP pin
multiplexing and configuration, see the pin multiplexing information in the device-specific data manual.
3944 Multichannel Audio Serial Port (McASP) SPRUH73E–October 2011–Revised May 2012
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