77V550S25DTG8 IDT, Integrated Device Technology Inc, 77V550S25DTG8 Datasheet - Page 13

• Manufacturer Part Number: 77V550S25DTG8
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of 77V550S25DTG8

• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 3.6V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 80
• Lead Free Status / RoHS Status: Compliant

Command Field Format
Command Field Format
Null Command
Null Command
managing workstation should look in the sub command field to see why this cell has been sent.
Null Command Format
Null Command Format
Read Data Command
Read Data Command
ready by reading the status register before reading data.
of the data bytes may contain random data (not zero).
Read Data Command Format
Read Data Command Format
IDT77V550
When transmitted to the Switch Manager this command generates a null cell. When a null command cell is received from a Switch Manager the
There are two possible situations when a null cell will be received by the Switch Manager:
1. This is a returned cell from a null command (no execution performed).
2. The switch has been manually reset or power cycled (all information in the switch has been lost) and a null cell was returned.
This command reads data from the Switch Controller. If bit 6 in the command field is set, the Switch Manager will first make sure the Controller is
The content fields (Data0-17) of a returned read command cell are only valid for the number of data bytes which is in the Data count field. The rest
Note: The command bit pattern is defined in the command field of Format Tables on pages 15-17.
Command
Sub Command
Data Count
DataCount 0-17
Command
Sub Command
Data Count
Data0 - 17
Bit Number
Field
Field
7
6
5
4
3
2
1
0
0x01
0xXX
0x00-0x12
0xXX
Value
0x00
0x00-0x01
0xXX
0xXX
Return an acknowledge cell signaling the execution of the current command.
Read the switch managers status register before doing a read or write.
Don’t care.
Don’t care.
Don’t care.
MSB of command bit pattern.
Bit of command bit pattern.
LSB of command bit pattern.
Value
Read data from Switch Controller and send it back to external control logic.
Don’t care.
Number of data registers to read from Switch Controller.
On return cell these fields will hold the read data.
Table 15 Read Data Command Format
Table 14 Null Command Format
Null command used in Transmit Cell Format bits 0-2.
Meaning on receiving cell at workstation:
Should be 0x00 when transmitted to Switch Manager.
Don’t care.
Don’t care.
13 of 19
0x00 Returning null cell command
0x01 Switch has been reset
Table 13
Description
Description
Description
June 22, 2001