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S3C2501X
ETHERNET CONTROLLER
7-43
7.5.1.4.1. Receive Frame Timing With/Without Error
If, during frame reception, both Rx_DV and Rx_er are asserted, a CRC error is reported for the current packet.
As each nibble of the destination address is received, the CAM block attempts to recognize it. After receiving the
last destination address nibble, if the CAM block rejects the packet, the receive block asserts the Rx_toss signal,
and discards any bytes not yet removed from the receive FIFO that came from the current packet. If this
operation leaves the FIFO empty, it drops Rx_rdy.
Figure 7-6 shows the MII receive data timing without error. The RX_DV signal, which entered the MII from the
PCS layer, will be ON when the PCS layer recovers the Rx_clk from the receive bit stream and delivers the
nibble data on RxD[3:0] data line. The RX_DV signal must be ON before the starting frame delimiter (SFD) is
received. When the Rx_DV signal is ON, the preamble and SFD parts of the frame header are delivered to MII,
synchronized with the 25MHz Rx_clk. (The carrier sense (CrS) signal was turned on during receive frame.)
As its response to the Rx_er signal, the MII immediately inserts an alternative data bit stream into the receive
data stream. As a result, the MAC discards this received error frame using the FCS.
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~~
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Rx_clk
Rx_DV
RxD [3:0]
Crs
Rx_er
~~
~~
Preamble
SFD
DA
SFD
Figure 7-9. Receiving Frame without Error
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~~
~~
~~
Rx_clk
Rx_DV
RxD [3:0]
Crs
Rx_er
~~
~~
Preamble
SFD
DA
SFD
Figure 7-10. Receiving Frame with Error
Содержание S3C2501X
Страница 1: ...S3C2501X 32 BIT RISC MICROPROCESSOR USER S MANUAL Revision 1 查询S3C2501X供应商 捷多邦 专业PCB打样工厂 24小时加急出货 ...
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Страница 275: ...MEMORY CONTROLLER S3C2501X 5 60 NOTES ...
Страница 289: ...I2C CONTROLLER S3C2501X 6 14 NOTES ...
Страница 373: ...GDMA CONTROLLER S3C2501X 9 24 NOTES ...
Страница 435: ...I O PORTS S3C2501X 12 12 NOTES ...
Страница 463: ...ELECTRICAL DATA S3C2501X 15 6 NOTES ...