EMC2103-2-AP-TR Standard Microsystems (SMSC), EMC2103-2-AP-TR Datasheet - Page 46

• Manufacturer Part Number: EMC2103-2-AP-TR
• Description: CLOSED LOOP RPM FAN CONTROLLER
• Manufacturer: Standard Microsystems (SMSC)

ADDR
Revision 0.88 (06-30-08)
17h
6.8
Table 5.1
R/W -
R/W
see
2
0
0
0
0
1
1
1
1
Writing to a read only register will have no affect. The data will be ignored.
Bit 4 - AUTOx - Enables the Automatic Beta detection algorithm for the External Diode X channel.
Bits 2 - 0 - BETAx[2:0] - hold a value that corresponds to a range of betas that the Beta Compensation
circuitry can compensate for. These three bits will always show the current beta setting used by the
circuitry. If the AUTO bit is set (default), then these bits may be overwritten with every temperature
conversion. If the AUTO bit is not set, then the value of these bits is used to drive the beta
compensation circuitry. In this case, these bits should be set with a value corresponding to the lowest
expected value of beta for the PNP transistor being used as a temperature sensing device.
See
circuitry is disabled. In this condition, the diode channels will function with default current levels and
will not automatically adjust for beta variation. This mode is used when measuring a discrete 2N3904
transistor or AMD thermal diode.
If the External Diode 3 channel is enabled, it will always use a beta setting of 111b.
These bits will be set to 111b if Beta Compensation is disabled - see
The Beta Configuration Registers are Software Locked.
REC Configuration Register
‘0’ - The Automatic Beta detection algorithm is disabled. The BETAx[3:0] bit settings will be used
to control the beta compensation circuitry. This bit is set to ‘0’ automatically if Beta Compensation
is disabled - see
‘1’ - The Automatic Beta detection algorithm is enabled. The circuitry will automatically detect the
transistor type and beta values and configure the BETAx[3:0] bits for optimal performance.
Table 6.12
Configuration
REGISTER
REC
for supported beta ranges. A value of 111b indicates that the beta compensation
BETAX[2:0]
Table 6.12 Beta Compensation Look Up Table
Table
Table 6.13 REC Configuration Register
1
0
0
1
1
0
0
1
1
B7
-
5.1.
B6
-
DATASHEET
B5
-
46
B4
-
0
0
1
0
1
0
1
0
1
RPM-Based Fan Controller with HW Thermal Shutdown
B3
-
REC3
B2
Table 5.1
REC2
B1
MINIMUM BETA
Disabled
< 0.176
< 0.111
< 0.08
< 0.29
< 0.48
< 2.33
< 0.9
REC1
B0
SMSC EMC2103
0000_01XXb
DEFAULT
Table 5.1
Datasheet
see