DRR_REG
Receive shift
register
(RSR)
Transmit shift
register
(XSR)
Receive buffer
(RB)
DXR_REG
mcbspi_dr
mcbspi_dx
To MPU /IVA2 ss
or sDMA
From MPU/IVA2 ss
or sDMA
Bit reorder
Transmit buffer
(XB)
Reverse
Reverse
Synchronisation and
buffering
mcbsp-024
DRR_REG
Receive Shift
Register
(RSR)
Transmit Shift
Register
(XSR)
Receive Buffer
(RB)
DXR_REG
mcbspi_dr
mcbspi_dx
To MPU /IVA2 ss
or sDMA
From MPU/IVA2 ss
or sDMA
Bit reorder
Transmit Buffer
(XB)
Reverse
Reverse
Synchronisation and
buffering
Transmit
Audio Buffer
Receive
Audio Buffer
mcbsp-068
Public Version
www.ti.com
McBSP Functional Description
All registers of McBSP data transfer paths are 32-bits wide.
and
illustrate the
McBSP data transfer paths.
CAUTION
The McBSP registers (DRR_REG and DXR_REG) are limited to 32-bit data
accesses (L4 Interconnect). 16-bit and 8-bit is not allowed and can corrupt
register content.
Figure 21-24. McBSP Data Transfer Paths
Figure 21-25. McBSP2 Data Transfer Paths
21.4.2.1 Data Transfer Process for 8- / 12- / 16- / 20- / 24- / 32-bits Long Words
CAUTION
For each data word length, one data occupies one 32-bit buffer word.
Receive data arrives on the mcbspi_dr pin and is shifted into the receive shift register (RSR). When a full
word (depending on the data length configuration) is received, the content of the shift register is copied
into the receive buffer (RB) if it is not full. When the RB threshold is reached the McBSP module asserts
DMA or interrupt request and the RB content is then transferred (the sDMA or the eDMA controller reads
the data receive register McBSPi.
).
Transmit data is written by the MPU subsystem, the IVA2.2 subsystem or the DMA controller to data
transmit register (McBSPi.
) using the McBSPi.
[1] XRDY
bit enable input (when a byte is not enabled, the byte value in the memory will contain the previous written
value). If there is no previous data in transmit shift register (XSR), the value from the transmit buffer (XB)
is copied to XSR; otherwise, the content is copied to the XSR when the last bit of the previous data is
shifted out on the mcbspi_dx pin.
3093
SWPU177N – December 2009 – Revised November 2010
Multi-Channel Buffered Serial Port
Copyright © 2009–2010, Texas Instruments Incorporated
Содержание OMAP36 Series
Страница 174: ...174 List of Tables SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 692: ...692 MPU Subsystem SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 1084: ...1084 IVA2 2 Subsystem SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 1990: ...1990 2D 3D Graphics Accelerator SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2334: ...2334 Memory Subsystem SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2700: ...2700 Memory Management Units SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2868: ...2868 HDQ 1 Wire SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2974: ...2974 UART IrDA CIR SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3054: ...3054 Multichannel SPI SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3462: ...3462 MMC SD SDIO Card Interface SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3508: ...3508 General Purpose Interface SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3584: ...3584 Initialization SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3648: ...3648 Debug and Emulation SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...