AM79C983A Advanced Micro Devices, AM79C983A Datasheet - Page 26

• Manufacturer Part Number: AM79C983A
• Description: Integrated Multiport Repeater 2 (IMR2)
• Manufacturer: Advanced Micro Devices

Error Packet Statistics
Sample Error Status is an 8-byte 4-deep FIFO that con-
tains statistical data on each packet having errors. The
data is read in the following order:
The FIFO is emptied by reading. If the FIFO is full, noth-
ing more is recorded in Sample Error Status. If the con-
trol port is accessed, the reading starts at the beginning
of the next location. If the data register is accessed after
the location has been completely read, the beginning of
the next location is automatically accessed.
Transceiver Interface
PAUI Ports
Packets are transferred between an IMR2 device and
transceivers via twelve Pseudo AUI (PAUI) ports. The
PAUI ports have the functionality of AUI ports, except that
they are single-ended signals rather than differential.
QuIET Device Control and Status Data Interface
Control and status data are passed between the IMR2
device and QuIET devices via a serial data interface.
26
Port Number
Status
Source Address
PENAO
PDRV
PTAG
PDAT
PCLK
Pre SFD DA SA
1 byte
1 byte:
6 bytes
FCS Error (LSB)
Non-Integral Bytes
Long
Short
Runt
Data Rate Error
Very Long Event (MSB)
Length in Bytes
Figure 4. Packet Port Signals
T/L Field
P R E L I M I N A R Y
Am79C983A
Data
Status data is on the SDATA[3:0] pins, and serial inter-
face control is on the DIR[1:0] pins. SDATA is I/O. For
interfacing with non-QuIET devices, both DIR[1] and
DIR[0] are required. DIR[1:0] is used to select groups
of four ports. For interfacing with QuIET devices, only
DIR[1] is required.
DIR[1] controls the direction of data travel. Each SDATA
pin corresponds to a QuIET device connected to a set
of four specific IMR2 device ports.
Typically, SDATA[3] is not used for a 12-port repeater.
However, a QuIET device can be attached to the AUI
port and the RAUI port (in normal mode) to make a 14-
port repeater. The remaining two ports on the QuIET
device can be connected to two ports on another IMR2
device. SDATA[3] provides the MAU management for
all four ports on this QuIET device.
QuIET Device Control and Status Data Interface
Operation
The interface has two modes of operation: QuIET de-
vice mode and Non-QuIET device mode. The QuIET
device mode is automatically selected when a QuIET
device is attached and used, and the Non-QuIET mode
is selected when another type of transceiver is used.
Note that it is possible for different sets of ports to use
different types of transceivers.
Pin
SDATA[0]
SDATA[1]
SDATA[2]
Stat1 Field
Stat2 Field
Port
PAUI [3:0]
PAUI [7:4]
PAUI [11:8]
FCS
19879B-8