17 registers 64-66h: minimum pwm duty cycle, Functional description – Rainbow Electronics LM96000 User Manual
Page 22
Functional Description
(Continued)
4.17 Registers 64-66h: Minimum PWM Duty Cycle
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
Lock?
64h
R/W
Fan1 PWM Minimum
7
6
5
4
3
2
1
0
80h
U
65h
R/W
Fan2 PWM Minimum
7
6
5
4
3
2
1
0
80h
U
66h
R/W
Fan3 PWM Minimum
7
6
5
4
3
2
1
0
80h
U
These registers specify the minimum duty cycle that the PWM will output when the measured temperature reaches the
Temperature LIMIT register setting.
This register becomes Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further attempts to write to this
register shall have no effect. After power up the default value is used whenever the Ready/Lock/Start/Override register Start bit
is cleared even though modifications to this register are possible.
TABLE 9. PWM Duty vs Register Setting for PWM Low Frequency Range
Current Duty
Value (Decimal)
Value (Hex)
0%
0
00h
0.3922%
1
01h
.
.
.
.
.
.
.
.
.
25.098%
64
40h
.
.
.
.
.
.
.
.
.
50.196%
128
80h
.
.
.
.
.
.
.
.
.
100%
255
FF
PWM Duty Cycle vs Register Setting for PWM High Frequency Range
22.5KHz PWM Frequency
PWM Duty Cycle
Level (%)
Value in Decimal
Value in Hex
0.00
0
0
6.25
1 - 15
01 - 0F
12.50
16 - 31
10 - 1F
18.75
32 - 47
20 - 2F
25.00
48 - 63
30 - 3F
31.25
64 - 79
40 - 4F
37.50
80 - 95
50 - 5F
43.75
96 - 111
60 - 6F
50.00
112 - 127
70 - 7F
56.25
128 - 143
80 - 8F
62.50
144 - 159
90 - 9F
68.75
160 - 175
A0 - AF
75.00
176 - 191
B0 - BF
81.25
192 - 207
C0 - CF
87.50
208 - 223
D0 - DF
93.75
224 - 239
E0 - EF
100.00
240 - 255
F0 - FF
24KHz PWM Frequency
PWM Duty Cycle
Level (%)
Value in Decimal
Value in Hex
0
0
0
6.67
1 - 16
01 - 10
13.33
17 - 33
11 - 21
20.00
34 - 50
22 - 32
26.67
51 - 67
33 - 43
33.33
68 - 84
44 - 54
40.00
85 - 101
55 - 65
46.67
102 - 118
66 - 76
53.33
119 - 136
77 - 88
60.00
137 - 153
89 - 99
66.67
154 - 170
9A - AA
73.33
171 - 187
AB - BB
80.00
188 - 204
BC - CC
86.67
205 - 221
CD - DD
93.33
222 - 238
DE - EE
100.00
239 - 255
EF - FF
LM96000
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