MDS213 Datasheet, PDF (47/120 Pages) Zarlink Semiconductor Inc – 12-Port 10/100Mbps + 1Gbps Ethernet Switch

MDS213
Data Sheet
The port status of the MDS213 is transmitted to an external decoder via a serial output channel. In the MDS213, we
support cascading of this serial output channel between two devices. One MDS213 is configured as the master, this
initiates the start of LED information frames, and serializes information bits. The MDS213 slave repeats the
information sent from the master and appends its own information bits. To cascade these two devices, we will need
to extend the number of LED pins from 3 to 5. Figure 17 shows two cascaded LED interfaces and the connections
between the MDS213s, the LED decoder, and the LED display.
11.1.1 Function Description
The LED interface employs the following signals:
Signal Name
Master Device Slave Device
LE_CLKO
LE_SYNCI
LE_SYNCO
LE_DI
LE_DO
Description
LED Clock-Synchronous LED clock provided by the slave device to LED
decoder at the system clock divided by 8 (~12.5Mhz).
A synchronous pulse -- defines the boundary between frames. The length
of each LED data frame is about 256 bits that shift out by LE_CLKO per bit.
A continuous serial stream of data for all status LEDs which repeat once
every frame time.
Table 7 - LED Signal Names and Descriptions
11.1.2 Port Status
In the MDS213, each port consists of 8 different LED status, represented by separate bits:
1. Flow Control
2. Transmitting Data
3. Receiving Data
4. Action (TxD or RxD)
5. Link UP/DOWN
6. Speed
7. Full Duplex/Half Duplex
8. Collision
In addition to the 13 ports of the MDS213, three extra user-defined status sets may be sent through the LED serial
channel for debugging or other applications, where each user-defined status set is also represented by 8 bits.
11.1.3 LED Interface Time Diagram
The Master needs to shift out (13+3)*8 status bits periodically. Thus, slave needs to shift out (13+3)*8 + (13+3)*8
status bits, which includes the status of the master device and itself.
The status of each port will be sampled by the LED State Machine every 20.5 µs, the time period of the frame. That
is, each LED data frame length equals (256)X 80nsec. Each frame is divided into two subframes: a master and a
slave sub-frame. Furthermore, each sub-frame is partitioned into 16 slots (13 MAC ports plus 3 user-defined sets)
and each slot will carry 8 status bits. The following figure shows the signal from the slave chip to LED decoder.
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Zarlink Semiconductor Inc.