Texas Instruments TMS320C6201 Reference Manual page 386

Multichannel Selection Operation
11.6 Multichannel Selection Operation
11.6.1 Multichannel Operation Control Registers
11-68
Multiple channels can be independently selected for the transmitter and receiver
by configuring the McBSP with a single-phase frame. Each frame represents a
time-division multiplexed data stream. The number of elements per frame repre-
sented by (R/X)FRLEN1 denotes the number of channels available for selection.
Thus, to save memory and bus bandwidth, multichannel selection allows inde-
pendent enabling of particular elements for transmission and reception. Up to
32 elements in a bit stream of up to 128 elements can be enabled at any given
time.
If a receive element is not enabled:
RRDY is not set to 1 upon reception of the last bit of the element.
RBR is not copied to DRR upon reception of the last bit of the element. Thus,
RRDY is not set active. This feature also implies that no interrupts or synchro-
nization events are generated for this element.
If a transmit element is not enabled:
DX is in the high impedance state.
A DXR-to-XSR transfer is not automatically triggered at the end of serial
transmission of the related element.
XEMPTY and XRDY are not affected by the end of transmission of the re-
lated serial element.
An enabled transmit element can have its data masked or transmitted. When data
is masked, the DX pin is forced to the high-impedance state even though the
transmit channel is enabled.
The following control registers are used in multichannel operation:
The multichannel control register (MCR)
The transmit channel enable register (XCER)
The receive channel enable register (RCER)