1893Y-10 IDT, Integrated Device Technology Inc, 1893Y-10 Datasheet - Page 61

• Manufacturer Part Number: 1893Y-10
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of 1893Y-10

• Lead Free Status / RoHS Status: Not Compliant

8.1.2 Management Register Bit Access
8.1.3 Management Register Bit Default Values
ICS1893 Rev C 6/6/00
The ICS1893 Management Registers include one or more of the following types of bits:
Table 8-3.
The tables in this chapter specify for each register bit the default value, if one exists. The ICS1893 sets all
Management Register bits to their default values after a reset.
ICS1893 Management Register bits.
Table 8-4.
Note:
Read-Only
Command Override
Write
Read/Write
Read/Write Zero
Register Bit Types
State of pin at reset
Default Condition
ICS1893 - Release
Management
The ICS1893 has a number of reserved bits throughout the Management Registers. Most of these
bits provide enhanced test modes. The Management Register tables provide the default values for
these bits. The STA must not change the value of these bits under any circumstance. If the STA
inadvertently changes the default values of these reserved register bits, normal operation of the
ICS1893 can be affected.
–
0
1
Description of Management Register Bit Types
Range of Possible Valid Default Values for ICS1893 Register Bits
Indicates there is no default value for the bit
Indicates the bit’ s default value is logic zero
Indicates the bit’ s default value is logic one
For some bits, the default value depends on the state (that is, the logic value) of a
particular pin at reset (that is, the logic value of a pin is latched at reset). An
example of pins that have a default condition that depends on the state of the pin
at reset are the PHY / LED pins (P0AC, P1CL, P2LI, P3TD, and P4RD) discussed
in the following sections:
Symbol
•
•
•
R/W0
R/W
CW
RO
Section 6.8, “ Status Interface”
Section 8.11, “ Register 16: Extended Control Register”
Section 9.3.2, “ Multi-Function (Multiplexed) Pins: PHY Address and LED Pins”
Bit
Copyright © 2000, Integrated Circuit Systems, Inc.
All rights reserved.
An STA can obtain the value of a RO register bit. However, it cannot
alter the value of (that is, it cannot write to) an RO register bit. The
ICS1893 isolates any STA attempt to write a value to an RO bit.
An STA can read a value from a CW register bit. However, write
operations are conditional, based on the value of the Command
Register Override bit (bit 16.15). When bit 16.15 is logic:
An STA can unconditionally read from or write to a R/W register bit.
An STA can unconditionally read from a R/W0 register bit, but only a
‘ 0’ value can be written to this bit.
•
•
Zero (the default), the ICS1893 isolates STA attempts to write to
the CW bits (that is, CW bits cannot be altered when bit 16.15 is
logic zero).
One, the ICS1893 permits an STA to alter the value of the CW bits
in the subsequent register write. (Bit 16.15 is self-clearing and
automatically clears to zero on the subsequent write.)
61
Default Value
Table 8-4
Description
Chapter 8 Management Register Set
lists the valid default values for
June, 2000