9.1 EDMA3 Resources
9.1.1 TCP2 Dedicated EDMA3 Resources
9.1.2 Special TCP2 EDMA3 Programming Considerations
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Programming
Note that several user channels can be programmed prior to starting the TCP2.
Table 42. EDMA3 Parameters in Standalone (SA) Mode
Direction
Transmit (DSP →TCP)Receive (TCP →DSP) Data Usage Required/Optional
Transmit Input configuration Send the input configuration Requiredparameters parameters
Transmit Systematics and parities Send the systematics and parities Required
Transmit Interleaver indexes Send the interleaver table Optional INTER bit
Receive Hard decisions Read the hard decisions Required
Receive Output parameters Read the output parameters Optional OUTF bit
Table 43. EDMA3 Parameters in Shared Processing (SP) Mode
Direction
Transmit (DSP →TCP)Receive (TCP →DSP) Data Usage Required/Optional
Transmit Input configuration Send the input configuration Requiredparameters parameters
Transmit Systematics and parities Send the systematics and parities Required
Transmit A prioris Send the a prioris Required except for firstiteration MAP1
Receive Extrinsics Read the extrinsics Required
Within the available 64 EDMA3 channels event sources, two are assigned to the TCP: event 30 and event31.
•Event 30 is associated to the TCP2 receive event (TCPREVT) and is used as the synchronizationevent for the EDMA3 transfer from the TCP2 to the DSP (receive).
•Event 31 is associated to the TCP2 transmit event (TCPXEVT) and is used as the synchronizationevent for the EDMA3 transfer from the DSP to the TCP2 (transmit).
The EDMA3 parameters consists of eight words as shown in Figure 99 . In the context of the TCP2, allEDMA3 transfers should follow ACNT * BCNT number of bytes in A_Sync Mode and ACNT *BCNT *CCNT number of bytes in AB_Sync Mode. The number of bytes should be a multiple of 8. For moreinformation, see the TMS320C6457 DSP Enhanced Direct Memory Access (EDMA3) Controller ReferenceGuide (SPRUGK6 ).
Figure 99. EDMA3 Parameters Structure
31 0
EDMA3 Channel Options Parameter (OPT)
EDMA3 Channel Source Address (SRC)
Number of arrays of length ACNT (BCNT) Number of bytes in array (ACNT)
EDMA3 Channel Destination Address (DST)
Destination 2nd Dimension Index (DSTBIDX) Source 2nd Dimension Index (SRCBIDX)
BCNTRLD LINK
Destination 3rd Dimension Index (DSTCIDX) Source 3rd Dimension Index (SRCCIDX)
Reserved Number of frames in block (CCNT)
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