Transmit Dma Transfers; Receive Dma Transfers - Texas Instruments OMAP5912 Reference Manual

Transmit DMA Transfers

Figure 43. Transmit DMA Transfers
TI peripheral bus
dma add
Ad0 Ad1
Val0 dum

Receive DMA Transfers

SPRU760B
A new transmit DMA transfer is initiated during the transmission of the last
channel of a frame, at which time all data in the transmit registers (TX_REGs)
has been moved to shift registers; the TX_REGs are now ready to be rewritten.
If N channels are used, the DMA controller successively accesses all
consecutive registers between TX_REG(0) and TX_REG(N-1). If some
channels between TX_REG(0) and TX_REG(N-1) are not used, the DMA
controller writes dummy values when addressing these unused registers (see
Figure 43).
ad
Adn
n-1
dum Valn
A receive DMA transfer is initiated after the reception of the last channel of a
frame, at which time all receive registers RX_REG have been updated and are
ready to be read. If N channels are used, the DMA controller successively
accesses all consecutive registers between RX_REG(0) and RX_REG(N-1).
If some channels between RX_REG(0) and RX_REG(N-1) are not used, the
DMA controller reads dummy values when addressing these unused registers
(see Figure 44).
Multichannel Serial Interfaces
MCSI
MCSI Tx
MCSI Tx
shift
registers
registers
Value 0 Value 0
Dummy 1 Empty 1
Dummy n-1 Empty n-1
Value n Value n
Empty n+1 Empty n+1
Empty N Empty N
Serial output
Value 0 Value n
Serial Interfaces 123