
1133
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Multichannel Audio Serial Port (McASP)
24.0.21.7.1 Loopback Mode Configurations
This is a summary of the settings required for digital loopback mode for TDM format:
•
The DLBEN bit in DLBCTL must be set to 1 to enable loopback mode.
•
The MODE bits in DLBCTL must be set to 01b for both the transmit and receive sections to use the
transmit clock and frame sync generator.
•
The ORD bit in DLBCTL must be programmed appropriately to select odd or even serializers to be
transmitters or receivers. The corresponding serializers must be configured accordingly.
•
The ASYNC bit in ACLKXCTL must be cleared to 0 to ensure synchronous transmit and receive
operations.
•
RMOD field in AFSRCTL and XMOD field in AFSXCTL must be set to 2h to 20h to indicate TDM
mode. Loopback mode does not apply to DIT or burst mode.
24.0.22 Reset Considerations
The McASP has two reset sources: software reset and hardware reset.
24.0.22.1 Software Reset Considerations
The transmitter and receiver portions of the McASP may be put in reset through the global control register
(GBLCTL). Note that a valid serial clock must be supplied to the desired portion of the McASP (transmit
and/or receive) in order to assert the software reset bits in GBLCTL. See
for details on
how to ensure reset has occurred.
The entire McASP module may also be reset through the Power and Sleep Controller (PSC). Note that
from the McASP perspective, this reset appears as a hardware reset to the entire module.
24.0.22.2 Hardware Reset Considerations
When the McASP is reset due to device reset, the entire serial port (including the transmitter and receiver
state machines, and other registers) is reset.
24.0.23 EDMA Event Support
The McASP-related EDMA events are shown in
.
Table 24-6. EDMA Events - McASP
Channel
Event Name
Event Description
0
AREVT0
McASP0 Receive Event
1
AXEVT0
McASP0 Transmit Event
24.0.24 Power Management
The McASP can be placed in reduced power modes to conserve power during periods of low activity. The
power management of the peripheral is controlled by the processor Power and Sleep Controller (PSC).
The PSC acts as a master controller for power management for all of the peripherals on the device. For
information on power management procedures using the PSC, see the
Power and Sleep Controller (PSC)
chapter.