DP83936AVF datasheet(50/104 Pages) NSC

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60 SONIC-T Registers (Continued)

646 Interrupt Status Register

(Continued)

Bit

Description

TXER TRANSMIT ERROR

Indicates that a packet has been transmitted with at least one of the following errors

Byte count mismatch (BCM)

Excessive collisions (EXC)

FIFO underrun (FU)

Excessive deferral (EXD)

The TXpktstatus field reveals the cause of the error(s)

TC GENERAL PURPOSE TIMER COMPLETE

Indicates that the timer has rolled over from 0000 0000h to FFFF FFFFh (See Section 6412)

RDE RECEIVE DESCRIPTORS EXHAUSTED

Indicates that all receive packet descriptors in the RDA have been exhausted This bit is set when the SONIC-T

detects EOL e 1 (See Section 547)

RBE RECEIVE BUFFER EXHAUSTED

Indicates that the SONIC-T has detected the Resource Read Pointer (RRP) is equal to the Resource Write Pointer

(RWP) This bit is set after the last field is read from the resource area (See Section 547)

Note 1

This bit will be set as the SONIC-T finishes using the second to last receive buffer and reads the last RRA descriptor This gives the system

an early warning of impending no resources

Note 2

The SONIC-T will stop reception of packets when the last RBA has been used and will not continue reception until additional receive buffers

have been added (ie RWP is incremented beyond RRP) and this bit has been reset

Note 3

If additional buffers have been added resetting this bit causes the SONIC-T to read the next resource descriptor pointed to by the RRP in

the Receive Resource Area Note that resetting this bit under this condition is similar to issuing the Read RRA command (setting the RRRA bit in the

Command Register) This bit should never be reset until after the additional resources have been added to the RRA

RBAE RECEIVE BUFFER AREA EXCEEDED

Indicates that during reception the SONIC-T has reached the end of the Receive Buffer Area Reception is aborted

and the SONIC-T fetches the next available resource descriptors in the RRA The buffer space is not re-used and an

RDA is not set up for the truncated packet (see Section 547)

CRC CRC TALLY COUNTER ROLLOVER

Indicates that the tally counter has rolled over from FFFFh to 0000h (See Section 6411)

FAE FRAME ALIGNMENT ERROR (FAE) TALLY COUNTER ROLLOVER

Indicates that the FAE tally counter has rolled over from FFFFh to 0000h (See Section 6411)

MP MISSED PACKET (MP) COUNTER ROLLOVER

Indicates that the MP tally counter has rolled over from FFFFh to 0000h (See Section 6411)

RFO RECEIVE FIFO OVERRUN

Indicates that the SONIC-T has been unable to access the bus before the receive FIFO has filled from the network

This condition is due to excessively long bus latency andor slow bus clock Note that FIFO underruns are indicated

in the TCR (See Section 351)

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DP83936AVF Datasheet(PDF) 50 Page - National Semiconductor (TI)

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