Datasheet

LM96000
SNAS234C –APRIL 2004–REVISED MARCH 2013 www.ti.com
– – [67-69h] Set the fan temperature limits.
– – [6A-6Ch] Set the temperature absolute limits.
– – [64-66h] Set the PWM minimum duty cycle.
– – [6D-6Eh] Set the temperature Hysteresis values.
2. [40h] Set bit 0 (START) to update fan control and limit register values and start fan control based on these
new values.
3. [40h] Set bit 1 (LOCK) to lock the fan limit and parameter registers (optional).
3.0 AUTO FAN CONTROL OPERATING MODE
The LM96000 includes the circuitry for automatic fan control. In Auto Fan Mode, the LM96000 will automatically
adjust the PWM duty cycle of the PWM outputs. PWM outputs are assigned to a thermal zone based on the fan
configuration registers. It is possible to have more than one PWM output assigned to a thermal zone. For
example, PWM outputs 2 and 3, connected to two chassis fans, may both be controlled by thermal zone 2. At
any time, the temperature of a zone exceeds its absolute limit, all PWM outputs will go to 100% duty cycle to
provide maximum cooling to the system.
4.0 REGISTER SET
Register Read/ Register Bit 7 Bit 0 Default
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Lock?
Address Write Name (MSB) (LSB) Value
20h R 2.5V 7 6 5 4 3 2 1 0 N/A
21h R VCCP_I 7 6 5 4 3 2 1 0 N/A
N
22h R 3.3V 7 6 5 4 3 2 1 0 N/A
23h R 5V 7 6 5 4 3 2 1 0 N/A
24h R 12V 7 6 5 4 3 2 1 0 N/A
25h R Process 7 6 5 4 3 2 1 0 N/A
or
(Zone1)
Temp
26h R Internal 7 6 5 4 3 2 1 0 N/A
(Zone2)
Temp
27h R Remote 7 6 5 4 3 2 1 0 N/A
(Zone3)
Temp
28h R Tach1 7 6 5 4 3 2 LEVEL1 LEVEL0 N/A
LSB
29h R Tach1 15 14 13 12 11 10 9 8 N/A
MSB
2Ah R Tach2 7 6 5 4 3 2 LEVEL1 LEVEL0 N/A
LSB
2Bh R Tach2 15 14 13 12 11 10 9 8 N/A
MSB
2Ch R Tach3 7 6 5 4 3 2 LEVEL1 LEVEL0 N/A
LSB
2Dh R Tach3 15 14 13 12 11 10 9 8 N/A
MSB
2Eh R Tach4 7 6 5 4 3 2 LEVEL1 LEVEL0 N/A
LSB
2Fh R Tach4 15 14 13 12 11 10 9 8 N/A
MSB
30h R/W Fan1 7 6 5 4 3 2 1 0 N/A
Current
PWM
Duty
10 Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated
Product Folder Links: LM96000