Texas Instruments TMS320C6457 DSP manual Priori Transfer

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∙Word count = 2 * ceil (frame_length/2)

∙BCNT = (Word count /2) (No of arrays of length ACNT)

∙DESTINATION ADDRESS: TCPSP (5001 0000h)

∙SRCBIDX = 8 (Source 2nd Dimension Index)

∙DSTBIDX = 8 (Destination 2nd Dimension Index)

∙SRCCIDX = 8 (Source 3rd Dimension Index)

∙DSTCIDX = 8 (Destination 3rd Dimension Index)

∙CCNT = 8 (No of frames in a block)

∙BCNTRLD: Don't care

∙LINK ADDRESS: See cases 1 and 2 below

Upon completion, this EDMA3 transfer is linked to one of the following:

1.The EDMA3 input configuration parameters transfer parameters of the next user-channel, if there is one ready to be decoded and the current decoding is a MAP0 from the first iteration.

2.Dummy EDMA3 transfer parameters, if there are no more user channels ready to be decoded.

9.3.1.3A Priori Transfer

This EDMA3 transfer to the a priori memory is a TCPXEVT chained and frame-synchronized transfer. This EDMA3 transfer is chained from the systematic and parity data transfer and occurs only when executing any MAP but the MAP0 of the first iteration; that is, the OPMOD bits in TCPIC0 must be set to 2h, 4h, and

6h respectively. The parameters should be set as:

∙OPTIONS:

–ITCCEN = 0 (Intermediate transfer complete chaining is disabled)

–TCCEN = 0 (Transfer complete chaining is disabled)

–ITCINTEN = 0 (Intermediate transfer complete interrupt is disabled)

–TCINTEN = 1 (Transfer complete interrupt is enabled)

–TCC = 1 to 63 (Transfer Complete Code)

–TCCMODE = 0 (Normal Completion)

–FWID = Don't care

–STAT = 0 (Entry is updated as normal)

–SYNCDIM = 1 (A-Sync. Each event triggers the transfer of ACNT elements.)

–DAM = 0 (Dst addressing within an array increments. Dst is not a FIFO.)

–SAM = 0 (Src addressing within an array increments. Source is not a FIFO.)

∙SOURCE ADDRESS: A priori start address (must be double-word aligned)

∙If the OPMOD == FIRST_SUB_FRAME

ACNT = 8 * ceil ((frame_length + prolog_length)/8) ⇒ (No of bytes in an array)

∙If the OPMOD == MIDDLE_SUB_FRAME

ACNT = 8 * ceil ((frame_length + 2 * prolog_length)/8) ⇒ (No of bytes in an array)

∙If the OPMOD == LAST_SUB_FRAME

ACNT = 8 * ceil ((frame_length + prolog_length)/8) ⇒ (No of bytes in an array)

∙BCNT = 1 (No of arrays of length ACNT)

∙DESTINATION ADDRESS: TCPAP (5004 0000h)

∙SRCBIDX = 0 (Source 2nd Dimension Index)

∙DSTBIDX = 0 (Destination 2nd Dimension Index)

∙SRCCIDX = 0 (Source 3rd Dimension Index)

∙DSTCIDX = 0 (Destination 3rd Dimension Index)

∙CCNT = 1 (No of frames in a block)

∙BCNTRLD: Don't care

∙LINK ADDRESS: See cases 1 and 2 below

Upon completion, this EDMA3 transfer is linked to one of the following:

72 TMS320C6457 Turbo-Decoder Coprocessor 2 SPRUGK1–March 2009

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