1102
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Multichannel Audio Serial Port (McASP)
McASP Audio FIFO (AFIFO)
The McASP Audio FIFO (AFIFO) provides additional data buffering for the McASP. The time it takes the
host CPU or DMA controller to respond to DMA requests from the McASP may vary; the additional
buffering provided by the AFIFO allows greater tolerance to such variations.
For convenience, the AFIFO is treated here as a block between McASP and the host/DMA controller (see
). Details on configuration of the AFIFO are provided in
.
Operation
This section discusses the operation of the McASP.
24.0.21.1 Setup and Initialization
This section discusses steps necessary to use the McASP module.
24.0.21.1.1 Considerations When Using a McASP
The following is a list of things to be considered for systems using a McASP:
24.0.21.1.1.1 Clocks
For each receive and transmit section:
•
External or internal generated bit clock and high frequency clock?
•
If internally generated, what is the bit clock speed and the high frequency clock speed?
•
Clock polarity?
•
External or internal generated frame sync?
•
If internally generated, what is frame sync speed?
•
Frame sync polarity?
•
Frame sync width?
•
Transmit and receive sync or asynchronous?
24.0.21.1.1.2 Data Pins
For each pin of each McASP:
•
McASP or GPIO?
•
Input or output?
24.0.21.1.1.3 Data Format
For each transmit and receive data:
•
Internal numeric representation (integer, Q31 fraction)?
•
I2S or DIT (transmit only)?
•
Time slot delay (0, 1, or 2 bit)?
•
Alignment (left or right)?
•
Order (MSB first, LSB first)?
•
Pad (if yes, pad with what value)?
•
Slot size?
•
Rotate?
•
Mask?