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Datasheet
FORCOL - When set, the FORCOL bit will force a collision by not deferring deliberately. This bit is set and cleared only by the CPU. When TXENA is enabled with no packets in the queue and while the FORCOL bit is set, the LAN91C111 will transmit a preamble pattern the next time a carrier is seen on the line. If a packet is queued, a preamble and SFD will be transmitted. This bit defaults low to normal operation. NOTE: The LATCOL bit in the EPHSR, setting up as a result of FORCOL, will reset TXENA to 0. In order to force another collision, TXENA must be set to 1 again.
LOOP - Loopback. General purpose output port used to control the LBK pin. Typically used to put the PHY chip in loopback mode.
TXENA - Transmit enabled when set. Transmit is disabled if clear. When the bit is cleared the LAN91C111 will complete the current transmission before stopping. When stopping due to an error, this bit is automatically cleared.
8.6Bank 0 - EPH Status Register
OFFSET | NAME | TYPE | SYMBOL |
2 | EPH STATUS REGISTER | READ ONLY | EPHSR |
This register stores the status of the last transmitted frame. This register value, upon individual transmit packet completion, is stored as the first word in the memory area allocated to the packet. Packet interrupt processing should use the copy in memory as the register itself will be updated by subsequent packet transmissions. The register can be used for real time values (like TXENA and LINK OK). If TXENA is cleared the register holds the last packet completion status.
HIGH | Reserved | LINK_ | Reserved | CTR | EXC | LOST | LATCOL | Reserved |
BYTE |
| OK |
| _ROL | _DEF | CARR |
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| 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
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LOW | TX | LTX | SQET | 16COL | LTX | MUL | SNGL | TX_SUC |
BYTE | DEFR | BRD |
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| MULT | COL | COL |
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| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
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LINK_OK - General purpose input port driven by nLNK pin inverted. Typically used for Link Test. A transition on the value of this bit generates an interrupt.
CTR_ROL - Counter Roll Over. When set one or more 4 bit counters have reached maximum count (15). Cleared by reading the ECR register.
EXC_DEF - Excessive Deferral. When set last/current transmit was deferred for more than 1518 * 2 byte times. Cleared at the end of every packet sent.
LOST_CARR - Lost Carrier Sense. When set indicates that Carrier Sense was not present at end of preamble. Valid only if MON_CSN is enabled. This condition causes TXENA bit in TCR to be reset. Cleared by setting TXENA bit in TCR.
LATCOL - Late collision detected on last transmit frame. If set a late collision was detected (later than 64 byte times into the frame). When detected the transmitter jams and turns itself off clearing the TXENA bit in TCR. Cleared by setting TXENA in TCR.
TX_DEFR - Transmit Deferred. When set, carrier was detected during the first 6.4 μs of the inter frame gap. Cleared at the end of every packet sent.
LTX_BRD - Last transmit frame was a broadcast. Set if frame was broadcast. Cleared at the start of every transmit frame.
Revision 1.91 | 48 | SMSC LAN91C111 REV C |
DATASHEET