DP83820BVUW National Semiconductor, DP83820BVUW Datasheet - Page 29

• Manufacturer Part Number: DP83820BVUW
• Description: IC INTERFACE CONTROLLER 208-PQFP
• Manufacturer: National Semiconductor

Specifications of DP83820BVUW

• Controller Type: Ethernet Controller, MAC/BIU
• Interface: IEEE 802.3
• Voltage - Supply: 3.3V
• Current - Supply: 150mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 208-MQFP, 208-PQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *DP83820BVUW

3.0 Functional Description
rxDescRead
rxFIFOblock
rxDescWrite
rxFragWrite
rxDescRefr
rxAdvance
rxIdle
state
FifoReady
CR:RXEN && !CRDD
CR:RXEN && CRDD
XferDone && !OWN
XferDone && OWN
(descCnt == 0) &&
(rxPktBytes > 0)
rxPktBytes == 0
link == NULL
link != NULL
FifoReady
XferDone
XferDone
XferDone
event
(rxPktCnt > 0) or (rxPktBytes > rxDrainThreshold) ... in other words, if we have a complete
packet in the FIFO (regardless of size), or the number of bytes that we do have is greater than
the rxDrainThreshold, then we are ready to begin draining the rxDataFifo.
(Continued)
Table 3-9 Receive State Tables
rxDescRead
rxDescWrite
rxDescWrite
rxDescRead
rxFIFOblock
rxFIFOblock
rxFragWrite
rxDescRefr
next state
rxAdvance
rxAdvance
rxIdle
rxIdle
29
start a burst transfer at address RXDP and a
length derived from RXCFG.
start a burst transfer to refresh the link field of the
current descriptor.
set ISR:RXIDLE.
start a burst transfer from the RxDataFIFO to host
memory at fragPtr. The length will be the
minimum of rxPktBytes and descCnt. Decrement
descCnt accordingly.
start a burst transfer to write the status back to
the descriptor, setting the OWN bit, and setting
the MORE bit. We'll continue the packet in the
next descriptor.
start a transfer to write the cmdsts back to the
descriptor, setting the OWN bit and clearing the
MORE bit, and filling in the final receive status
(CRC, FAE, SIZE, etc.).
RXDP <- rxDescCache.link. Clear CRDD. Start a
burst transfer at address RXDP with a length
derived from RXCFG:MAXF.
set CRDD. Set ISR:RXIDLE.
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