SH7672 datasheet(501/1292 Pages) RENESAS

Part #	SH7672

Description	32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7670 Series

PDF	1292 Pages

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Manufacturer	RENESAS [Renesas Technology Corp]

Direct Link	http://www.renesas.com

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Section 13 Ethernet Controller Direct Memory Access Controller (E-DMAC)

Rev. 1.00 Nov. 14, 2007 Page 475 of 1262

REJ09B0437-0100

(2) Receive Descriptor

Figure 13.3 shows the relationship between a receive descriptor and the receive buffer. In frame

reception, the E-DMAC performs data rewriting up to a receive buffer 16-byte boundary,

regardless of the receive frame length. Finally, the actual receive frame length is reported in the

lower 16 bits of RD1 in the descriptor. Data transfer to the receive buffer is performed

automatically by the E-DMAC to give a one frame/one buffer or one frame/multi-buffer

configuration according to the size of one received frame.

Receive descriptor

Receive buffer

Valid receive data

RFS9 to

RFS0

RCS15 to RCS0

RD0

RBL

RDL

RD1

RBA

Padding (4 bytes)

RD2

31 30 29 28 27 26 25

1615

Figure 13.3 Relationship between Receive Descriptor and Receive Buffer

SH7672 Datasheet(PDF) 501 Page - Renesas Technology Corp