KSZ8851SNLI Micrel Inc, KSZ8851SNLI Datasheet - Page 52

• Manufacturer Part Number: KSZ8851SNLI
• Manufacturer: Micrel Inc

Specifications of KSZ8851SNLI

• Operating Supply Voltage (typ): 3.3V
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 32
• Lead Free Status / RoHS Status: Supplier Unconfirmed

Receive Frame Header Byte Count Register (0x7E – 0x7F): RXFHBCR
This register indicates the received frame header byte count information, the received frames are reported in RXFCTR
register. This register contains the total number of bytes information for the frame received and the CPU can read so
many times same as the frame count value in the RXFCTR.
TXQ Command Register (0x80 – 0x81): TXQCR
This register is programmed by the Host CPU to issue a transmit command to the TXQ. The present transmit frame in
the TXQ memory is queued for transmit.
August 2009
Micrel, Inc.
Bit
3
2
1
0
Bit
15-12
11-0
Bit
15-3
2
1
0
-
-
-
-
-
-
-
0x0
0x0
0x0
Default Value
Default Value
Default Value
R/W
RO
RO
RO
RO
R/W
RO
RO
R/W
RW
RW
RW
RW
Description
RXFT Receive Frame Type
When this bit is set, it indicates that the frame is an Ethernet-type frame (frame length is
greater than 1500 bytes). When clear, it indicates that the frame is an IEEE 802.3 frame.
This bit is not valid for runt frames.
RXFTL Receive Frame Too Long
When this bit is set, it indicates that the frame length exceeds the maximum size of 2000
bytes. Frames that are too long are passed to the host only if the pass bad frame bit is
set.
Note: Frame too long is only a frame length indication and does not cause any frame
truncation.
RXRF Receive Runt Frame
When this bit is set, it indicates that a frame was damaged by a collision or had a
premature termination before the collision window passed.
Runt frames are passed to the host only if the pass bad frame bit is set.
RXCE Receive CRC Error
When this bit is set, it indicates that a CRC error has occurred on the current received
frame.
CRC error frames are passed to the host only if the pass bad frame bit is set.
Description
Reserved
RXBC Receive Byte Count
This field indicates the present received frame byte size.
Description
Reserved
AETFE Auto-Enqueue TXQ Frame Enable
When this bit is written as 1, the KSZ8851SNL will enable current all TX frames prepared
in the TX buffer are queued to transmit automatically.
The bit 0 METFE has to be set 0 when this bit is set to 1 in this register.
TXQMAM TXQ Memory Available Monitor
When this bit is written as 1, the KSZ8851SNL will generate interrupt (bit 6 in ISR register)
to CPU when TXQ memory is available based upon the total amount of TXQ space
requested by CPU at TXNTFSR (0x9E) register.
Note: This bit is self-clearing after the frame is finished transmitting. The software should
wait for the bit to be cleared before set to 1 again.
METFE Manual Enqueue TXQ Frame Enable
When this bit is written as 1, the KSZ8851SNL will enable current TX frame prepared in
the TX buffer is queued for transmit, this is only transmit one frame at a time.
Note: This bit is self-clearing after the frame is finished transmitting. The software should
wait for the bit to be cleared before setting up another new TX frame.
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KSZ8851SNL/SNLI
M9999-083109-2.0