Texas Instruments TMS320C6457 DSP manual EDMA3 Resources, EDMA3 Parameters in Standalone SA Mode

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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	Required
	parameters	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	Required
	parameters	parameters
Transmit	Systematics and parities	Send the systematics and parities	Required
Transmit	A prioris	Send the a prioris	Required except for first
			iteration MAP1
Receive	Extrinsics	Read the extrinsics	Required

9.1EDMA3 Resources

9.1.1TCP2 Dedicated EDMA3 Resources

Within the available 64 EDMA3 channels event sources, two are assigned to the TCP: event 30 and event 31.

∙Event 30 is associated to the TCP2 receive event (TCPREVT) and is used as the synchronization event 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 synchronization event for the EDMA3 transfer from the DSP to the TCP2 (transmit).

9.1.2Special TCP2 EDMA3 Programming Considerations

The EDMA3 parameters consists of eight words as shown in Figure 99. In the context of the TCP2, all EDMA3 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 more information, see the TMS320C6457 DSP Enhanced Direct Memory Access (EDMA3) Controller Reference Guide (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)
SPRUGK1–March 2009	TMS320C6457 Turbo-Decoder Coprocessor 2	65
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