TC654(2002) View Datasheet(PDF) - Microchip Technology
Part Name
Description
Manufacturer
TC654 Datasheet PDF : 36 Pages
| |||
TC654/TC655
6.4 STATUS REGISTER (STATUS)
The Status Register provides all the information about
what is going on within the TC654/TC655 devices. Fan
fault information, VIN status, RPM counter overflow,
and over temperature indication are all available in the
Status Register. The Status Register is an 8-bit Read
only register with bits 6 and 7 unused. See Register 6-
4 below for the bit descriptions.
REGISTER 6-4: STATUS REGISTER (STATUS)
U-0
U-0
R-X
R-0
R-0
R-X
R-0
R-0
—
—
OTF
R2CO R1CO VSTAT
F2F
F1F
bit 7
bit 0
bit 7-6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Unimplemented: Read as ‘0’
OTF: Over Temperature Fault Condition
For the TC654/TC655 device, this bit is set to the proper state immediately at startup and is
therefore treated as an unknown (X). If VIN is greater than the threshold required for 100% duty
cycle on VOUT (2.6 V typical), then the bit will be set to a ‘1’. If it is less than the threshold, the
bit will be set to ‘0’. This is determined at power-up.
1 = Over temperature condition has occurred.
0 = Normal operation. VIN is less than 2.6 V.
R2CO: RPM2 Counter Overflow
1 = Fault condition. The maximum RPM reading of 12775 RPM in register RPM2 has been
exceeded. This bit will automatically reset to zero when the RPM reading comes back into
range.
0 = Normal operation. RPM reading is within limits (default).
R1CO: RPM1 Counter Overflow
1 = Fault condition. The maximum RPM reading of 12775 RPM in register RPM1 has been
exceeded. This bit will automatically reset to zero when the RPM reading comes back into
range.
0 = Normal operation. RPM reading is within limits (default).
VSTAT: VIN Input Status
For the TC654/TC655 devices, the VIN pin status is checked immediately at power-up. If no
external thermistor or voltage output network is connected (VIN is open), this bit is set to a ‘1’.
If an external network is detected, this bit is set to ‘0’. If the VIN pin is open and SMBus operation
has not been selected in the Configuration Register, the VOUT duty cycle will default to 39.33%.
1 = VIN is open.
0 = Normal operation. voltage present at VIN.
F2F: Fan2 Fault
1 = Fault Condition. The value for fan RPM in the RPM2 Register has fallen below the value
set in the FAN_FAULT2 Threshold Register. The speed of Fan 2 is too low and a fault con-
dition is being indicated. The FAULT output will be pulled low at the same time. This fault
bit can be cleared using the Fan Fault Clear bit (FFCLR (bit 7<0>)) in the Configuration
Register.
0 = Normal Operation (default).
F1F: Fan1 Fault
1 = Fault Condition. The value for fan RPM in the RPM1 Register has fallen below the value
set in the FAN_FAULT1 Threshold Register. The speed of Fan 1 is too low and a fault con-
dition is being indicated. The FAULT output will be pulled low at the same time. This fault
bit can be cleared using the Fan Fault Clear bit (FFCLR (bit 7<0>)) in the Configuration
Register.
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
DS21734A-page 20
2002 Microchip Technology Inc.
Share Link: 