Freescale Semiconductor MPC860T Switch User Manual


 
1-2
MPC860T (Rev. D) Fast Ethernet Controller Supplement
MOTOROLA
PRELIMINARYÑSUBJECT TO CHANGE WITHOUT NOTICE
The MPC860T integrates three separate processing blocks. The Þrst two, common with all
MPC860 devices, are as follows:
¥ A high-performance PowerPCª core that can be used as a general purpose
processor for application programming
¥ A RISC engine embedded in the communications processor module (CPM)
designed to provide the communications protocol processing provided by the
MPC860MH.
¥ A 10/100 Fast Ethernet controller with integrated FIFOs and bursting DMA.
Because the FEC block is implemented independently, the MPC860T provides
high-performance Fast Ethernet connectivity without affecting the performance of
the CPM. All of the performance and functionality of the MPC860MH is fully
supported, including Ethernet.
Additionally, as the CPM of the MPC860T is based on the CPM of the MPC860MH,
support for the QMC protocol is also provided. This enables the MPC860T to provide
protocol processing (HDLC or transparent mode) for 64 time-division multiplexed
channels at 50 MHz. This support for multichannel protocol processing and 10/100
Ethernet in one chip makes the MPC860T ideal for products such as high-performance,
low-cost remote access routers.
Note that for existing parts, adding FEC functionality affects port D signal multiplexing.
1.3 Comparison with the MPC860
The MPC860T is pin compatible with the MPC860, so it may be used in similar
applications with minimal modiÞcation. The electrical characteristics and mechanical data
are nearly identical, with the exception of port D and the four no connect pins on the
MPC860, which make up the media independent interface (MII). Most of the MII pins are
multiplexed with the port D pins.
1.4 Features
The following sections summarize key FEC features.
¥ 10/100 base-T support
Ñ Full compliance with the IEEE 802.3u standard for 10/100 base-T
Ñ Support for three different physical interfaces: 100-Mbps 802.3
media-independent interface (MII), 10-Mbps 802.3 MII, and 10-Mbps 7-wire
interface
Ñ Large on-chip transmit and receive FIFOs to support a variety of bus latencies
Ñ Retransmission from the transmit FIFO after a collision
Ñ Automatic internal ßushing of the receive FIFO for runts and collisions
Ñ External BD tables of user-deÞnable size allow nearly unlimited ßexibility in
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