9TCS1085
MOBILE ACCESS™—CLOCK SYNTHESIZER, TEMPERATURE SENSOR, & PWM FAN CONTROLLER FOR PORTABLE DEVICES
IDT®
MOBILE ACCESS™—CLOCK SYNTHESIZER, TEMPERATURE SENSOR, & PWM FAN CONTROLLER FOR PORTABLE DEVICES 34
9TCS1085 REV 0.7 012012
System Direct Tachometer Control
The system will directly write to register byte[32], bit[7:0] and
byte[33], bit[7:3] a desired TACH setting.
The tachometer setting is related to the fan speed by the
RPM equation, “Formula 1”.
Setting Minimum and Maximum Tachometer
RPM
The minimum and maximum tachometer settings can be set
for the fan faults.
a. TACH_MIN - byte[31], bit[7:0]
b. TACH_MAX - byte[30, bit[7:0]
Fan Fault Conditions
The fan fault conditions will be activated and reported if the
minimum or maximum fan speed is detected. During a
FAULT1, maximum fan speed, 9TCS1085 will stop the fan
and then wait for the FAULT1 flag to be cleared. For a
FAULT2 condition, stalled fan, 9TCS1085 will go through the
spin-up procedure to try to start the fan. The number of
attempts to try to restart the fan is programmable. The fan
fault conditions are reported via register on byte[37], bit[1;0].
Fan Fault Conditions
The number of times for spin-up retries:
Byte[32], bit[7:0] Logic "1" selects Tachometer
Reading
Bit[7] 4096
Bit[6] 2048
Bit[5] 1024
Bit[4] 512
Bit[3] 256
Bit[2] 128
Bit[1] 64
Bit[0] 32
Byte[33], bit[7:3] Logic "1" selects Tachometer
Reading
Bit[7] 16
Bit[6] 8
Bit[5] 4
Bit[4] 2
Bit[3] 1
Byte[31], bit[7:0] Logic "1" selects Tachometer
Reading
Bit[7] 512
Bit[6] 256
Bit[5] 128
Bit[4] 64
Bit[3] 32
Bit[2] 16
Bit[1] 8
Bit[0] 4
Byte[30], bit[7:0] Logic "1" selects Tachometer
Reading
Bit[7] 4096
Bit[6] 2048
Bit[5] 1024
Bit[4] 512
Bit[3] 256
Bit[2] 128
Bit[1] 64
Bit[0] 32
Byte[37], bit[1:0] Logic "1" = FAULT CONDITION
Bit[1] Fault1 - Fan speed too fast
Bit[0] Fault2 - Fan speed too slow
Byte[25], bit[2:1] Number of Spin-up Attempts
[00] 3
[01] (default) 4
[10] 5
[11] 6
