AMC6821SDBQG4 Datasheet, PDF (41/56 Pages) Texas Instruments – Intelligent Temperature Monitor and PWM Fan Controller

AMC6821
www.ti.com
SBAS386C – MAY 2006 – REVISED JULY 2007
In a write operation, the data written are the actual DCY driving the PWM-Out pin in the software DCY control
mode. However, in all other control modes, the data being written are not used to drive the PWM. Instead, it is
stored in a temporary register, and controls the PWM immediately after the control mode is changed to the
software DCY control mode.
Fan Characteristics Register (Address 0x20, Value After Power-On or Reset = 0x1D)
BIT
NAME
DEFAULT
DESCRIPTION
7
FSPD
0
Fan Spin Disable Bit
When FSPD = 1, the fan spin-up process is disabled.
When FSPD = 0, the fan spin-up process is enabled.
6
0
0
Reserved
5
PWM2
0
PWM Frequency Bits
4
PWM1
1
PWM2
PWM1
PWM0
PWM Frequency
3
PWM0
1
When PWM-MODE pin is floating or tied to V_DD
0
0
0
10Hz
0
0
1
15Hz
0
1
0
23Hz
0
1
1
30Hz (Default)
1
0
0
38Hz
1
0
1
47Hz
1
1
0
62Hz
1
1
1
94Hz
When PWM-MODE pin is tied to GND
0
0
0
1kHz
0
0
1
10kHz
0
1
0
20kHz
0
1
1
25kHz (Default)
1
0
0
30kHz
1
0
1
40kHz
1
1
0
40kHz
1
1
1
40kHz
2
STIME2
1
Spin-Up Time Bit
1
STIME1
0
STIME2
STIME1
STIME0
Spin-Up Time
(in Seconds)
0
STIME0
1
0
0
0
0.2
0
0
1
0.4
0
1
0
0.6
0
1
1
0.8
1
0
0
1
1
0
1
2 (Default)
1
1
0
4
1
1
1
8
This register specifies the PWM frequency and the fan spin-up functions.
Copyright © 2006–2007, Texas Instruments Incorporated
Product Folder Link(s): AMC6821
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