Rainbow Electronics LM81 - Manual (Page 29)

Functional Description
(Continued)
13.10 VID/Fan Divisor Register — Address 47h
Power on default – < 7:4 > is 0101, and < 3:0 > is mapped to VID < 3:0 >
Bit Name Read/Write Description
0-3 VID < 3:0 > Read Only The VID < 3:0 > inputs from the Pentium/PRO power supplies that indicate the
operating voltage (e.g. 1.5V to 2.9V).
4-5 FAN1 RPM
Control Read/Write FAN1 Speed Control.
< 5:4 > = 00 - divide by 1;
< 5:4 > = 01 - divide by 2;
< 5:4 > = 10 - divide by 4;
< 5:4 > = 11 - divide by 8.
6-7 FAN2 RPM
Control Read/Write FAN2 Speed Control.
< 7:6 > = 00 - divide by 1;
< 7:6 > = 01 - divide by 2;
< 7:6 > = 10 - divide by 4;
< 7:6 > = 11 - divide by 8.
13.11 Serial Bus Address Register — Address 48h
Power on default – Serial Bus address < 6:0 > = 010 11(A1)(A0) and < 7 > = 0 binary
Bit Name Read/Write Description
0-1 Serial Bus
Address Read Only Serial Bus address < 1:0 > = A1 A0
2-6 Serial Bus
Address Read/Write Serial Bus address < 6:2 > = 010 11
7 Reserved Read/Write
13.12 VID4 Register — Address 49h
Power on default – < 7:1 > = 100 000, < 0 > = VID4.
Bit Name Read/Write Description
0 VID4 Read Only VID4 input from Pentium/PRO power supply that indicate the operating voltage of
the processor (e.g. 1.5V to 2.9V).
1-7 Reserved Read/Write
13.13 Temperature Configuration Register — Address 4Bh
Power on default – < 7:0 > = 0000 0001 binary
Bit Name Read/Write Description
0-1 Temperature
Interrupt Mode
Select Bits Read/Write The state of these bits select the interrupt mode for INT as described below.
< 1:0 > = 00 or < 1:0 > = 11: Repetitive Interrupt Mode
< 1:0 > = 01: One-Time Interrupt Mode
< 1:0 > = 10: Comparator Mode
2-6 Reserved Read/Write
7 Temperature
Resolution Read Only For 8-bit plus sign temperature resolution: < 7 > = LSB ( 0.5˚C)
LM81
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