TC654 View Datasheet(PDF) - Microchip Technology
Part Name
Description
MFG CO.
'TC654' PDF : 36 Pages View PDF
TC654/TC655
6.3 CONFIGURATION REGISTER
(CONFIG)
The Configuration Register is an 8-bit read/writable
multi-function control register. This register allows the
user to clear fan faults, select RPM resolution, select
VOUT duty cycle (fan speed) control method, select the
fan current pulses per rotation for fans 1 and 2 (for fan
RPM calculation) and put the TC654/TC655 device into
a Shutdown mode to save power consumption. See
Register 6-3 below for the Configuration Register bit
descriptions.
REGISTER 6-3: CONFIGURATION REGISTER (CONFIG)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-1
FFCLR
RES
DUTYC F2PPR F2PPR
bit 7
R/W-0
F1PPR
R/W-1
F1PPR
R/W-0
SDM
bit 0
bit 7
bit 6
bit 5
bit 4-3
bit 2-1
bit 0
FFCLR: Fan Fault Clear
1 = Clear Fan Fault. This will reset the Fan Fault bits in the Status Register and the FAULT output.
0 = Normal Operation (default)
RES: Resolution Selection for RPM Output Registers
1 = RPM Output Registers (RPM1 and RPM2) will be set for 25 RPM (9-bit) resolution.
0 = RPM Output Registers (RPM1 and RPM2) will be set for 50 RPM (8-bit) resolution. (default)
DUTYC: Duty Cycle Control Method
1 = The VOUT duty cycle will be controlled via the SMBus interface. The value for the VOUT duty cycle
will be taken from the duty cycle register (DUTY_CYCLE).
0 = The VOUT duty cycle will be controlled via the VIN analog input pin. The VOUT duty cycle value will
be between 30% and 100% for VIN values between 1.62V and 2.6V typical. If the VIN pin is open
when this mode is selected, the VOUT duty cycle will default to 39.33%. (default)
F2PPR: Fan 2 Pulses Per Rotation
The TC654/TC655 device uses this setting to understand how many current pulses per revolution Fan 2
should have. It then uses this as part of the calculation for the fan 2 RPM value in the RPM2 Register.
See Section 7.7 “Determining Current Pulses Per Revolution of Fans” for application information on
determining your fan’s number of current pulses per revolution.
00 = 1
01 = 2 (default)
10 = 4
11 = 8
F1PPR: Fan 1 Pulses Per Rotation
The TC654/TC655 device uses this setting to understand how many current pulses per revolution Fan 1
should have. It then uses this as part of the calculation for the fan 1 RPM value for the RPM1 Register.
See Section 7.7 “Determining Current Pulses Per Revolution of Fans” for application information on
determining your fan’s number of current pulses per revolution.
00 = 1
01 = 2 (default)
10 = 4
11 = 8
SDM: Shutdown Mode
1 = Shutdown mode. See Section 4.9 “Low-Power Shutdown Mode” for more information on low-
power Shutdown mode.
0 = Normal operation. (default)
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
’1’ = Bit is set
U = Unimplemented bit, read as ‘0’
’0’ = Bit is cleared
x = Bit is unknown
2002-2014 Microchip Technology Inc.
DS20001734C-page 19
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