STLC1502 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'STLC1502' PDF : 81 Pages View PDF
STLC1502
tion from the ARM controller.
• In receive, when the complete frame is stored in memory, the DMAC asserts the interrupt for the
ARM that can read the frame.
• In transmit the DMAC provides an interrupt when the complete frame is transferred.
6.5 Ethernet Switch
The Ethernet switch block interfaces two MAC cores to implement a 3-port Ethernet Fast switch and MAC layer
for the Embedded VoIP network software.
Main features of the block are:
• Internal FIFOs for easy DMA transfers.
• Full duplex support using separate Tx, Rx FIFOs.
• Fast switching using hardware connections between the two MAC cores. ARM microcontroller is not
involved in the switching function.
• Support for priority mechanism for voice packets, using store-and-forward procedure for incoming
data packets.
• VLAN support
• 10/100 Mb/s data transfer rates
• The MAC cores provide 2 MII interfaces to connect two external PHYs.
The device works normally as a bidirectional switch between the two ports. When the following conditions hap-
pen the device triggers additional operations:
• Received frame destination MAC address matches device MAC address. The frame is transferred to
memory using DMA, and is not switched to the other port.
• A frame has to be transmitted by the device. In this case the block waits for the end of the current
frame being switched if any. If the frame is a voice frame, as soon as the line is free the block starts
transfer of the frame. Eventual incoming frames in the same direction are stored and forwarded after
the voice frame has been sent.
The block diagram of the Ethernet switch is shown below:
21/81
Share Link: 
