TC654_14 Datasheet, PDF (14/38 Pages) Microchip Technology – Dual SMBus™ PWM Fan Speed Controllers With Fan Fault Detection

TC654/TC655
When the TC654/TC655 devices are brought out of a
Shutdown mode by resetting SDM (bit 0<0>) in the
Configuration Register, all of the registers (except for
the Configuration and FAN_FAULT1 and 2 registers)
assume their default power-up states. The Configura-
tion Register and the FAN_FAULT1 and 2 Registers
maintain the states they were in prior to the device
being put into the Shutdown mode. Since these are the
registers which control the parts operation, the part
does not have to be reprogrammed for operation when
it comes out of Shutdown mode.
4.10 SMBus Interface (SCLK & SDA)
The TC654/TC655 feature an industry-standard, 2-wire
serial interface with factory-set addresses. By commu-
nicating with the TC654/TC655 device registers, func-
tions like PWM duty cycle, low-power Shutdown mode
and fan RPM threshold can be controlled. Critical infor-
mation, such as fan fault, over-temperature and fan
RPM, can also be obtained via the device data regis-
ters. The available data and control registers make the
TC654/TC655 devices very flexible and easy to use. All
of the available registers are detailed in Section 6.0
“Register Set”.
4.11 SMBus Slave Address
The slave address of the TC654/TC655 is 0011 011
and is fixed. This address is different from industry-
standard digital temperature sensors (like TCN75) and,
therefore, allows the TC654/TC655 to be utilized in
systems in conjunction with these components. Please
contact Microchip Technology Inc. if alternate
addresses are required.
DS20001734C-page 14
 2002-2014 Microchip Technology Inc.