PIC16F74T-E/L【PDF 68/104 页】IC MCU FLASH 4KX14 A/D 44PLCC

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Sheet目录3890

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Micrel, Inc.

KSZ8851-16MLLJ

March 2010

M9999-030210-1.0

TXQ Memory Information Register (0x78 – 0x79): TXMIR

This register indicates the amount of free memory available in the TXQ of the QMU module.

Bit

Default Value

R/W

Description

15-13

Reserved.

12-0

TXMA Transmit Memory Available

The amount of memory available is represented in units of byte. The TXQ memory is

used for both frame payload, control word.

Note: Software must be written to ensure that there is enough memory for the next

transmit frame including control information before transmit data is written to the TXQ.

0x7A – 0x7B: Reserved

Receive Frame Header Status Register (0x7C – 0x7D): RXFHSR

This register indicates the received frame header status information, the received frames are reported in RXFCTR

as the frame count value in the RXFCTR.

Bit

Default Value

R/W

Description

RXFV Receive Frame Valid

When this bit is set, it indicates that the present frame in the receive packet memory is

valid. The status information currently in this location is also valid.

When clear, it indicates that there is either no pending receive frame or that the current

frame is still in the process of receiving.

Reserved

RXICMPFCS Receive ICMP Frame Checksum Status

When this bit is set, the KSZ8851 received ICMP frame checksum field is incorrect.

RXIPFCS Receive IP Frame Checksum Status

When this bit is set, the KSZ8851 received IP header checksum field is incorrect.

RXTCPFCS Receive TCP Frame Checksum Status

When this bit is set, the KSZ8851 received TCP frame checksum field is incorrect.

RXUDPFCS Receive UDP Frame Checksum Status

When this bit is set, the KSZ8851 received UDP frame checksum field is incorrect.

9-8

Reserved

RXBF Receive Broadcast Frame

When this bit is set, it indicates that this frame has a broadcast address.

RXMF Receive Multicast Frame

When this bit is set, it indicates that this frame has a multicast address (including the

broadcast address).

RXUF Receive Unicast Frame

When this bit is set, it indicates that this frame has a unicast address.

RXMR Receive MII Error

When set, it indicates that there is an MII symbol error on the received frame.

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.

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