KSZ8851SNL-BBE-EVAL Micrel Inc, KSZ8851SNL-BBE-EVAL Datasheet - Page 24

• Manufacturer Part Number: KSZ8851SNL-BBE-EVAL
• Description: BOARD EVAL MAC/PHY FOR KSZ8851
• Manufacturer: Micrel Inc
• Series: LinkMD®r

Specifications of KSZ8851SNL-BBE-EVAL

• Design Resources: BeagleBoard Zippy2
• Main Purpose: Interface, Ethernet Controller (PHY and MAC)
• Embedded: No
• Utilized Ic / Part: KSZ8851SNL
• Primary Attributes: 1 Port, 100BASE-TX/10BASE-T
• Secondary Attributes: SPI Interface, LinkMD Cable Diagnostics
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 576-3602; KSZ8851SNL-BBE-EVL; ZIPPY2

0 contains only opcode (10: read command, 11: write command) and the following is read/write data phase.
Queue Management Unit (QMU)
The Queue Management Unit (QMU) manages packet traffic between the MAC/PHY interface and the system host. It has
built-in packet memory for receive and transmit functions called TXQ (Transmit Queue) and RXQ (Receive Queue). Each
queue contains 12KB for RXQ and 6KB for TXQ of memory with back-to-back, non-blocking frame transfer performance.
It provides a group of control registers for system control, frame status registers for current packet transmit/receive status,
and interrupts to inform the host of the real time TX/RX status.
Transmit Queue (TXQ) Frame Format
The frame format for the transmit queue is shown in the following Table 6. The first word contains the control information
August 2009
Micrel, Inc.
SCLK
SCLK
CSN
CSN
SO
SO
SI
SI
D7
X
D6
X
1
Read Data Byte 3
RXQ Read Command Byte 0
D5
X
0
High Impedance
D4
X
X
D3
X
X
D2
X
X
D1
X
X
D0
X
X
Figure 10. TXQ FIFO Write Timing
Figure 9. RXQ FIFO Read Timing
D7
X
X
D6
D7
X
X
Read Data Byte 4
D5
D6
X
X
Read Data Byte 1
D4
D5
X
X
D3
X
D4
X
24
D2
X
D3
X
D1
X
D2
X
D0
X
D1
X
X
D0
D7
X
D7
X
D6
X
Read Data Byte 2
D6
X
Read Data Byte N
D5
X
D5
X
D4
X
D4
X
D3
X
D3
X
KSZ8851SNL/SNLI
D2
X
D2
X
M9999-083109-2.0
D1
X
D1
X
D0
X
D0
X