ZL50404
2.2.2
CPU MAC Module (CMAC)
Data Sheet
The CPU Media Access Control (CMAC) module provides the necessary buffers and control interface between the
Frame Engine (FE) and the external CPU device. It support a register access mechanism via the serial interface.
This port is denoted as port 8.
2.2.3
MII MAC Module (MMAC)
The MII Media Access Control (MMAC) module provides the necessary buffers and control interface between the
Frame Engine (FE) and the external physical device (PHY). The MMAC implements an MII interface.
The MMAC of the ZL50404 device meets the IEEE 802.3 specification. It is able to operate in 10M/100M either Half
or Full Duplex mode with a back pressure/flow control mechanism. Furthermore, it will automatically retransmit
upon collision for up to 16 total transmissions.
This port is denoted as port 9. The PHY address for the PHY device connected to the MMAC port has to be 10h.
2.2.4
PHY Addresses
The table below provides an overview of the PHY addresses required for each port in order for the MDIO
auto-negotiation to work between the ZL50404 MAC and the PHY device. If a different PHY address is used, then
the port must be manually brought up and the PHY will need to be polled for link status via the MIIC/D registers.
MAC Port
RMAC Port 0
RMAC Port 1
...
RMAC Port 3
CMAC Port 8
MMAC Port 9
PHY Address
0x08
0x09
...
0x0B
NA
0x10
Table 4 - PHY Addresses
2.3
Management Module
The CPU can send a control frame to access or configure the internal network management database. The
Management Module decodes the control frame and executes the functions requested by the CPU.
This module is only active in managed mode. In unmanaged mode, no control frame is accepted by the device.
2.4
Frame Engine
The main function of the frame engine is to forward a frame to its proper destination port or ports. When a frame
arrives, the frame engine parses the frame header (64 bytes) and formulates a switching request, sent to the
search engine, to resolve the destination port. The arriving frame is moved to the internal memory. After receiving a
switch response from the search engine, the frame engine performs transmission scheduling based on the frame’s
priority. The frame engine forwards the frame to the MAC module when the frame is ready to be sent.
2.5
Search Engine
The Search Engine resolves the frame’s destination port or ports according to the destination MAC address (L2) by
searching the database. It also performs MAC learning, priority assignment, and trunking functions.
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