Driver copies to tx buffer initiates dma dma occurs

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Driver copies to Tx buffer, initiates DMA. DMA occurs to FIFO from Tx buffer. After DMA , FIFO sends pkt on wire. After sending full pkt to wire NIC interrupts to Driver. Driver updates pointers and stats.
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SUSHMA RAWAL 16 Transmit Logic Adds preamble and start of frame delimiter to the beginning of the frame. Calculates and adds CRC to the end of the frame Handles the access protocol including automatic retransmission
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SUSHMA RAWAL 17 Transmit logic Transmit data is sent from the FIFO, one byte at a time. Preamble, SOF delimiter and CRC added to frame. If the transmitter gets a FIFO empty status during transmission without also getting an End of Packet Transmission is stopped & tx underrun interrupt is activated. The transmitter remains stopped until the interrupt is cleared.
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SUSHMA RAWAL 18 Tx Errors Tx FIFO Underrun: If FIFO is exhausted during transmission Out of Window Collision Tx Abort Carrier Sense Lost When packet txmitted to wire Tx OK or TxErr Interrupt can be generated.
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SUSHMA RAWAL 19 Receive NIC gets packet in FIFO Automatically DMAs to Rx Ring buffer with status bytes in front indic length and Rx status After full pkt sent to Rx buffer NIC interrupts Interrupt Routine copies from Rx buffer to socket buffer and informs network interface queue.
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SUSHMA RAWAL 20 Receive P C I I/ F Tx FIFO Rx FIFO Tx/Rx Logic INTERRUPT LOGIC & REG Pkt Disc
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SUSHMA RAWAL 21 Receiver Logic Functions The receiver logic of the network interface performs the following: Communicates the incoming data to the receiving FIFO. Checks the destination address of the incoming frame. Checks the CRC of the incoming frame. Checks the length of the incoming frame.
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SUSHMA RAWAL 22 Data Transfer to Receiving FIFO • When receiver is enabled, the incoming data is transferred, to receiving FIFO.
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