Datasheet

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5.0 Buffer Management (Continued)
DP83815
Table 5-5 Transmit State Tables
Figure 5-5 Transmit State Diagram
State Event Next State Actions
txIdle CR:TXE && !CTDD txDescRead Start a burst transfer at address TXDP and a length
derived from TXCFG.
CR:TXE && CTDD txDescRefr Start a burst transfer to refresh the link field of the current
descriptor.
txDescRefr XferDone txAdvance
txDescRead XferDone && OWN txFIFOblock
XferDone && !OWN txIdle Set ISR:TXIDLE.
txFIFOblock FifoAvail txFragRead Start a burst transfer into the TxDataFIFO from fragPtr.
The length will be the minimum of txFifoAvail and
descCnt.
Decrement descCnt accordingly.
(descCnt == 0) &&
MORE
txDescWrite Start a burst transfer to write the status back to the
descriptor, clearing the OWN bit.
(descCnt == 0) &&
!MORE
txAdvance Write the value of TXDP to the txDataFIFO as a handle.
txFragRead XferDone txFIFOblock
txDescWrite XferDone txAdvance
txAdvance link != NULL txDescRead TXDP <- txDescCache.link. Clear CTDD. Start a burst
transfer at address TXDP with a length derived from
TXCFG.
link == NULL txIdle Set CTDD. Set ISR:TXIDLE. Clear CR:TXE.
txDescRefr
txIdle
txDescRead
txFifoBlocktxDescWrite
txAdvance
txFragRead
CR:TXE && CTDD
CR:TXE && !CTDD
link = NULL
XferDone
XferDone
XferDone
XferDone && OWN
XferDone && !OWN
link != NULL
descCnt == 0 && !(cmdsts & MORE)
descCnt == 0 && (cmdsts & MORE)
FifoAvail
Obsolete