t1
t2
t3
FAN_TACHx
FIGURE 36 – FAN TACHOMETER INPUT TIMING
NAME
DESCRIPTION
Pulse Time (1/2 Revolution Time=30/RPM)
Pulse High Time
MIN
4tTACH
3tTACH
tTACH
TYP
MAX
UNITS
µsec
µsec
1
1
t1
t2
t3
Pulse Low Time
µsec
Note 1: tTACH is the clock used for the tachometer counter. It is 30.52 * DVSR, where the divisor (DVSR) is
programmed in the Fan Control register.
t1
t2
LEDx
FIGURE 37 – LED OUTPUT TIMING
NAME
t1
t2
DESCRIPTION
MIN
1
0
TYP
MAX
2
UNITS
sec
sec
Period
Blink ON Time
0.51
Note 1: The blink rate is programmed through Bits[1:0] in LEDx register. When Bits[1:0]=00, LED is OFF.
Bits[1:0]=01 indicates LED blink at 1Hz rate with a 50% duty cycle (0.5 sec ON, 0.5 sec OFF). Bits[1:0]=10
indicates LED blink at ½ Hz rate with a 25% duty cycle (0.5 sec ON, 1.5 sec OFF). When Bits[1:0]=11, LED
is ON.
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