HD6417618 RENESAS [Renesas Technology Corp], HD6417618 Datasheet - Page 319

• Manufacturer Part Number: HD6417618
• Description: 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7618 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

(2)
Figure 12.3 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.
RD0
RD1
RD2
Receive Descriptor
Receive descriptor
31 30 29 28 27 26
31
31
R
A
C
T
Figure 12.3 Relationship between Receive Descriptor and Receive Buffer
R
D
E
L
R
F
P
1
R
F
P
0
RBL
R
E
F
Padding (4 bytes)
Section 12 Ethernet Controller Direct Memory Access Controller (E-DMAC)
16
RBA
RFS26 to RFS0
15
RDL
0
0
0
Rev. 6.00 Jun. 12, 2007 Page 287 of 610
Receive buffer
Valid receive data
REJ09B0131-0600