SIDETONE core
Transmitter
Receiver
McBSP3
Registers for data,
clock and
frame-synchronization
control and monitoring
Registers for
multichannel control
and monitoring
2 SPCR_REGs
2 RCR_REGs
2 XCR_REGs
2 SRGR_REGs
PCR_REG
2 MCR_REGs
8 RCER_REGs
8 XCER_REGs
Transmit shift
register
(XSR)
RINTCLR_REG
ROVFLCLR_REG
2 THRSH_REGs
RCCR_REG
DXR_REG
DRR_REG
XINTCLR_REG
XCCR_REG
DX
DR
CLKS
CLKXO
CLKXI
CLKX
FSXO
FSXI
FSX
Interface clock domain
Functional clock domain
{
{
SGAINCR_REG
ST_McBSP3_IRQ
Data processing unit
Ch1 process
GAIN
FIR
Ch0 process
GAIN
FIR
Receive buffer (RB)
FIFO (128
32 bit words)
×
SFIRCR_REG
Receive shift
register
(RSR)
{
Interrupt
to CPU
Synchronization
events to DMA
controller
McBSP3_IRQ_TX
McBSP3_IRQ_RX
McBSP3_IRQ
McBSP3_DMA_RX
McBSP3_DMA_TX
McBSP3_ICLK
McBSP3_SWAKEUP
PRCM
Interrupt
to CPU
Sample rate
generator
CLKX
CLKR
FS generated
CLK generated
CLKR
FSR
FSX
CLKX
CLKS
Clock and
frame logic
FSX_int
FSR_int
FSR_int
CLKR_int
CLKX_int
L4
interconnect
L
4
in
terface
L
4
in
terface
L4
interconnect
Transmit buffer (XB)
FIFO (128
32 bit words)
×
mcbsp-023
Pin block
Public Version
McBSP Functional Description
www.ti.com
Figure 21-23. McBSP3 Block Diagram
21.4.2 McBSP Data Transfer Process
For McBSP1, McBSP3, McBSP4, and McBSP5 modules, receive and transmit operations are
triple-buffered (512 bytes buffers organized in 32-bit words are used).
For the McBSP2 module, receive and transmit operations are quadruple-buffered (5K bytes buffers
organized in 32-bit words are used). Receive and transmit buffers are separated in two memories: The
same buffer as the others McBSP modules (1K bytes) and an audio buffer (4K bytes). The audio buffer is
the largest one and is clocked by the interface clock, while the other buffer is used for synchronizing data
to/from the audio buffer with the functional transmit/receive clock domains.
shows this
implementation in the McBSP2 data transfer paths.
3092
Multi-Channel Buffered Serial Port
SWPU177N – December 2009 – Revised November 2010
Copyright © 2009–2010, Texas Instruments Incorporated