Operating From 3.3 V Standby; Xnor Tree Test Mode; Power-On Default - Analog Devices ADT7460 Manual

Table 40. PWM Duty Cycle Registers
Register Description
0x30 PWM1 duty cycle
0x31 PWM2 duty cycle
0x32 PWM3 duty cycle
By readin he g t PWMx current duty
keep track of th e current duty c
when the fans a re running in automa
or in aco ust ic e nhancement m
VARY PWM D UTY
CYCLE WITH 8-BIT
RESOLUTION
Figure 5 3. C ontr ol PWM Duty Cycle

OPERATING FROM 3.3 V STANDBY

The ADT 60 74 has been specifically d
3.3 V STBY sup ply. In computers tha
the co re v oltag of the proces e
using t he dyn am ic TMIN mo
the p roce ssor ould change w
the d ynamics o f the system under dyna
Likew ise , when monitoring THERM , the HERM
be d isable d du ing these states. r
Def ault
0xFF (100%)
0xFF (100%)
0xFF (100%)
cycle gisters, users c re
ycle on ea ch PWM output ven
tic f an speed co ntrol ode
ode.
Manually w ith a Reso lut ion of 0
esig ned to o pera te fr
t sup rt S3 po and S5 s es,
sor is lower ed in the states se
de, lowerin he cor g t e v oltage f
the CPU tem per atur e a nd cha e
mic TMIN contro
timer s uld
T

XNOR TREE TEST MODE

The ADT7460 includes an XNOR tree test mode. This mode is
useful for in-circuit test equipment at board-level testing. By
applying stimulus to the pins included in the XNOR tree, it is
p ossib to de le
F ure 54 shows t ig
an
t est mod e.
, e
T he XN OR
m
XNOR t ree
.39 %

POWER-ON DEFAULT

The ADT7460 does not monitor temperatu
d efaul n po t o
om a
i s enab d by s ing t le
tat
( t 0, A ress 0x40) to 1. The Bi dd
. If
u p. This is becaus the BHVR b
o
c onf igur atio
ng
default.
l.
ho
Rev. C | Page 33 of 52
tec t open s or shor ts on t he sy
he s ignals tha t ar e exercis
tree t t is invoked es by set ting B
test enable register (Reg. 0x6F)
TACH1
TACH2
TACH3
TACH4
PWM2
PWM3 PWM1/XTO
Figure 54. X NOR Tr ee Test
wer -up. M onitorin g of t emper
ett he start bi t in c onfigu
fan s run at f
e its (Bits <7
n reg ers are set t ist o 1 00 (fans r
ADT7460
stem bo ard.
ed in the XN R tree O
it 0 (X EN) o he f t
.
re an d fan speed by
ature and fa n spe ed
ratio n Regist r 1 e
ull sp eed on ower- p
:5>) in the PWMx
un fu ll speed) by