
Advanced 10/100 Repeater with Integrated Management
—
LXT9860/9880
Datasheet
Document #: 248987
Revision#: 003
Rev Date: 08/07/01
111
6.8.1
Device/Revision Register
The value of this register follows the same scheme as the device identification register found in the
IEEE 1149.1 specification. The upper 4 bits correspond to silicon stepping. The next 16 bits store
a Part ID Number. The next 11 bits contain a JEDEC Manufacturer ID. Bit zero is
‘
1
’
if the chip is
the first in a stack. The encoding scheme used for the Product ID field is implementation
dependent.
6.8.2
LED Control Registers
The LED Control Registers and bit assignments are described in
Table 78
.
6.8.3
LED Global Control Register
This register allows software to have a measure of control over the Global Fault LED; it can read
status of LED mode.
If a manager is present the default for the Global Fault LED is 11, else it is 01. Bits (5:4) state what
LED mode the chip is in (
“
00
”
= mode 1, 01
”
= mode 2,
“
10
”
= mode 3 and
“
11
”
= mode 4). These
bits are read-only because the LED mode is set only via pins.
When writing this register, all other bits in this register are reserved and may have default = 1 or 0.
6.8.4
Port LED Control Register
This register (refer to
Table 80
) is used to encode the measure of control software has over the port
LEDs. The LED control encodings are listed in
Table 81
.
Table 77. Device/Revision Register Bit Assignment
31:28
27:12
11:8
7:1
0
Version
Part No.
Jedec Continuation Characters
JEDEC ID
1
1st in Chain
2
0000
8-port = 0010 0110 1001 1000
0000
111 1110
See Note 2
6-port = 0010 0110 1000 0100
1. The JEDEC ID is an 8-bit identifier. However, the MSB is for parity only and is ignored.
Intel
’
s JEDEC ID is FE (1111 1110) which becomes 111 1110.
2. First Chain Bit = 0 if ChipID
≠
00.
First Chain Bit = 1 if ChipID = 00.
Table 78. Global Fault LED Bit Assignments
31:6
5:4
3:2
1:0
Reserved
Bit 31:8: Write as 1; Ignore on read
Bit 7: Write as 0; Ignore on read
Bit 6: Write as 1; Ignore on read
Mode
Select
Global
Fault
Reserved
Write as 0; Ignore on read