SH7763 Datasheet, PDF (1016/2026 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC Engine Family SH-4A Series

Section 23 Gigabit Ethernet Controller (GETHER)
(b) Receive Descriptor 1 (RD1)
In RD1, the user specifies the data length of a receive buffer usable by the corresponding
descriptor. After reception of a frame, RD1 indicates the length of a frame received by the E-
DMAC.
The user should set RD1 before the start of a read by the E-DMAC.
Bit
Initial
Bit
Name Value R/W Description
31 to 16 RBL All 0 R/W Receive Buffer Data Length (in bytes, to be specified with a
32-byte boundary)
These bits set the length of data that can be received by the
corresponding receive buffer with an integral multiple of 32
bytes.
The maximum receive buffer data length is between 64
kbytes and 32 bytes (H'FFE0).
15 to 0 RDL All 0 R
Receive Data Length
These bits indicate the data length of a receive frame stored
in the receive buffer.
Receive data transferred to the receive buffer does not
include CRC data (4 bytes) placed at the end of a frame. As
a receive frame length, the number of bytes (valid data
bytes) not including CRC data are reported.
In single-frame/multi-buffer (descriptor) operation, only the
receive data length of the last descriptor is valid. The
receive data length of an intermediate descriptor has no
meaning.
The maximum frame length that can be received is:
When padding function is invalid: 64 kbytes between 1 byte
(H'FFFF)
When padding function is valid: 64 kbytes between 32 bytes
(H'FFE0)
Rev. 1.00 Oct. 01, 2007 Page 950 of 1956
REJ09B0256-0100