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DP8390DV 数据表(PDF) 29 Page - National Semiconductor (TI) |
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DP8390DV 数据表(HTML) 29 Page - National Semiconductor (TI) |
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29 / 56 page ![]() 100 Internal Registers (Continued) D7 D6 D5 D4 D3 D2 D1 D0 MAR0 FB7 FB6 FB5 FB4 FB3 FB2 FB1 FB0 MAR1 FB15 FB14 FB13 FB12 FB11 FB10 FB9 FB8 MAR2 FB23 FB22 FB21 FB20 FB19 FB18 FB17 FB16 MAR3 FB31 FB30 FB29 FB28 FB27 FB26 FB25 FB24 MAR4 FB39 FB38 FB37 FB36 FB35 FB34 FB33 FB32 MAR5 FB47 FB46 FB45 FB44 FB43 FB42 FB41 FB40 MAR6 FB55 FB54 FB53 FB52 FB51 FB50 FB49 FB48 MAR7 FB63 FB62 FB61 FB60 FB59 FB58 FB57 FB56 If address Y is found to hash to the value 32 (20H) then FB32 in MAR4 should be initialized to ‘‘1’’ This will cause the NIC to accept any multicast packet with the address Y NETWORK TALLY COUNTERS Three 8-bit counters are provided for monitoring the number of CRC errors Frame Alignment Errors and Missed Pack- ets The maximum count reached by any counter is 192 (C0H) These registers will be cleared when read by the CPU The count is recorded in binary in CT0 – CT7 of each Tally Register Frame Alignment Error Tally (CNTR0) This counter is incremented every time a packet is received with a Frame Alignment Error The packet must have been recognized by the address recognition logic The counter is cleared after it is read by the processor 76543210 CNTR0 CT7 CT6 CT5 CT4 CT3 CT2 CT1 CT0 CRC Error Tally (CNTR1) This counter is incremented every time a packet is received with a CRC error The packet must first be recognized by the address recognition logic The counter is cleared after it is read by the processor 76543210 CNTR1 CT7 CT6 CT5 CT4 CT3 CT2 CT1 CT0 Frames Lost Tally Register (CNTR2) This counter is incremented if a packet cannot be received due to lack of buffer resources In monitor mode this coun- ter will count the number of packets that pass the address recognition logic 76543210 CNTR2 CT7 CT6 CT5 CT4 CT3 CT2 CT1 CT0 FIFO This is an eight bit register that allows the CPU to examine the contents of the FIFO after loopback The FIFO will con- tain the last 8 data bytes transmitted in the loopback packet Sequential reads from the FIFO will advance a pointer in the FIFO and allow reading of all 8 bytes 76543210 FIFO DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 Note The FIFO should only be read when the NIC has been programmed in loopback mode NUMBER OF COLLISIONS (NCR) This register contains the number of collisions a node expe- riences when attempting to transmit a packet If no colli- sions are experienced during a transmission attempt the COL bit of the TSR will not be set and the contents of NCR will be zero If there are excessive collisions the ABT bit in the TSR will be set and the contents of NCR will be zero The NCR is cleared after the TXP bit in the CR is set 76543210 NCR NC3 NC2 NC1 NC0 110 Initialization Procedures The NIC must be initialized prior to transmission or recep- tion of packets from the network Power on reset is applied to the NIC’s reset pin This clearssets the following bits Register Reset Bits Set Bits Command Register (CR) TXP STA RD2 STP Interrupt Status (ISR) RST Interrupt Mask (IMR) All Bits Data Control (DCR) LAS Transmit Config (TCR) LB1 LB0 The NIC remains in its reset state until a Start Command is issued This guarantees that no packets are transmitted or received and that the NIC remains a bus slave until all ap- propriate internal registers have been programmed After initialization the STP bit of the command register is reset and packets may be received and transmitted Initialization Sequence The following initialization procedure is mandatory 1) Program Command Register for Page 0 (Command Register e 21H) 2) Initialize Data Configuration Register (DCR) 3) Clear Remote Byte Count Registers (RBCR0 RBCR1) 4) Initialize Receive Configuration Register (RCR) 5) Place the NIC in LOOPBACK mode 1 or 2 (Transmit Configuration Register e 02H or 04H) 6) Initialize Receive Buffer Ring Boundary Pointer (BNDRY) Page Start (PSTART) and Page Stop (PSTOP) 7) Clear Interrupt Status Register (ISR) by writing 0FFh to it 8) Initialize Interrupt Mask Register (IMR) 9) Program Command Register for page 1 (Command Register e 61H) i)Initialize Physical Address Registers (PAR0-PAR5) ii)Initialize Multicast Address Registers (MAR0-MAR7) iii)Initialize CURRent pointer 10) Put NIC in START mode (Command Register e 22H) The local receive DMA is still not active since the NIC is in LOOPBACK 11) Initialize the Transmit Configuration for the intended val- ue The NIC is now ready for transmission and recep- tion 29 |
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