Section 23 Gigabit Ethernet Controller (GETHER)
Rev. 1.00 Oct. 01, 2007 Page 954 of 1956
REJ09B0256-0100
(4) Descriptor
Pointer
The E-DMAC controls the transmit and receive descriptor addresses in memory and the
processing priority by using the following registers.
1. Registers related to a transmit descriptor
•
TDLAR: Address of the start descriptor in a list of transmit descriptors.
•
TDFAR: Address of the transmit descriptor to be processed
•
TDFXR: Address of the transmit descriptor that finished processing (set by a write-back
operation) last
•
TDFFR (DL bit): Indicates whether the TDLE value of the transmit descriptor specified by
TDFXR is 1 or not.
2. Registers related to receive descriptor:
•
RDLAR: Address of the start descriptor in a list of receive descriptors.
•
RDFAR: Address of the receive descriptor to be processed
•
RDFXR: Address of the receive descriptor that finished processing (set by a write-back
operation) last
•
RDFFR (DL bit): Indicates whether the RDLE value of the receive descriptor specified by
RDFXR is 1 or not.
Transmit descriptors and receive descriptors have a ring structure. When the TDLE (RDLE) value
of the processed transmit (receive) descriptor is 0, the next descriptor will be processed. The next
descriptor is the transmit (receive) descriptor at the address obtained by adding the processed
transmit (receive) descriptor address to the descriptor length specified by the DL bit in EDMR.
When the TDLE (RDLE) value of the processed transmit (receive) descriptor is 1, the transmit
descriptor indicated by TDLAR (RDLAR) will be processed next. Figure 23.7 shows the
relationship between the transmit/receive descriptor ring and read pointer.
The transmit descriptor list must be large enough to point to five or more transmit frames. If four
or less transmit frames are pointed to in a list, E-DMAC operation is not guaranteed. Accordingly,
do not set that all the transmit descriptors in a ring are used by four or less descriptors. The receive
descriptor list does not have this restriction. For example, one receive frame can use all receive
descriptors in a list.
In the initial setting, the start address of a descriptor list must be set to TDLAR (RDLAR) and
TDFAR (RDFAR), and the end descriptor address of the descriptor list to TDFXR (RDFXR) by
the software.
The E-DMAC updates TDFAR (RDFAR), TDFXR (RDFXR) and the DL bit in TDFFR (DL bit in
RDFFR) each time a descriptor is processed.
Summary of Contents for SH7763
Page 2: ...Rev 1 00 Oct 01 2007 Page ii of lxvi ...
Page 122: ...Section 2 Programming Model Rev 1 00 Oct 01 2007 Page 56 of 1956 REJ09B0256 0100 ...
Page 144: ...Section 3 Instruction Set Rev 1 00 Oct 01 2007 Page 78 of 1956 REJ09B0256 0100 ...
Page 170: ...Section 4 Pipelining Rev 1 00 Oct 01 2007 Page 104 of 1956 REJ09B0256 0100 ...
Page 282: ...Section 7 Caches Rev 1 00 Oct 01 2007 Page 216 of 1956 REJ09B0256 0100 ...
Page 378: ...Section 9 Interrupt Controller INTC Rev 1 00 Oct 01 2007 Page 312 of 1956 REJ09B0256 0100 ...
Page 514: ...Section 12 DDR SDRAM Interface DDRIF Rev 1 00 Oct 01 2007 Page 448 of 1956 REJ09B0256 0100 ...
Page 630: ...Section 13 PCI Controller PCIC Rev 1 00 Oct 01 2007 Page 564 of 1956 REJ09B0256 0100 ...
Page 710: ...Section 16 Clock Pulse Generator CPG Rev 1 00 Oct 01 2007 Page 644 of 1956 REJ09B0256 0100 ...
Page 732: ...Section 17 Watchdog Timer and Reset WDT Rev 1 00 Oct 01 2007 Page 666 of 1956 REJ09B0256 0100 ...
Page 752: ...Section 18 Power Down Mode Rev 1 00 Oct 01 2007 Page 686 of 1956 REJ09B0256 0100 ...
Page 772: ...Section 19 Timer Unit TMU Rev 1 00 Oct 01 2007 Page 706 of 1956 REJ09B0256 0100 ...
Page 824: ...Section 21 Compare Match Timer CMT Rev 1 00 Oct 01 2007 Page 758 of 1956 REJ09B0256 0100 ...
Page 1124: ...Section 26 I 2 C Bus Interface IIC Rev 1 00 Oct 01 2007 Page 1058 of 1956 REJ09B0256 0100 ...
Page 1350: ...Section 30 SIM Card Module SIM Rev 1 00 Oct 01 2007 Page 1284 of 1956 REJ09B0256 0100 ...
Page 1484: ...Section 33 Audio Codec Interface HAC Rev 1 00 Oct 01 2007 Page 1418 of 1956 REJ09B0256 0100 ...
Page 1560: ...Section 35 USB Host Controller USBH Rev 1 00 Oct 01 2007 Page 1494 of 1956 REJ09B0256 0100 ...
Page 1720: ...Section 37 LCD Controller LCDC Rev 1 00 Oct 01 2007 Page 1654 of 1956 REJ09B0256 0100 ...
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