EMC2103 Standard Microsystems Corporation, EMC2103 Datasheet - Page 65

• Manufacturer Part Number: EMC2103
• Description: Rpm-based Fan Controller with HW Thermal Shutdown
• Manufacturer: Standard Microsystems Corporation

ADDR
78h
79h
RPM-Based Fan Controller with HW Thermal Shutdown
Datasheet
SMSC EMC2103
6.34
ADDR
E1h
R/W
R/W
R/W
R/W
R/W
The Look Up Table Registers hold the 40 entries of the Look Up Table that controls the drive of the
PWM. As the temperature channels are updated, the measured value for each channel is compared
against the respective entries in the Look Up Table and the associated drive setting is loaded into an
internal shadow register and stored.
The bit weighting for temperature inputs represents °C and is compared against the measured data.
Note that the LUT entry does not include a sign bit. The Look Up Table does not support negative
temperature values and the MSBit should not be set for a temperature input.
Each temperature channel threshold shares the same hysteresis value. When the measured
temperature for any of the channels meets or exceeds the programmed threshold, the drive setting
associated with that threshold is used. The temperature must drop below the threshold minus the
hysteresis value before the drive setting will be set to the previous value.
If the RPM based Fan Speed Control Algorithm is used, the TACH Target is updated after every
conversion. It is always set to the minimum TACH Target that is stored by the Look Up Table. The
PWM duty cycle is updated based on the RPM based Fan Speed Control Algorithm configuration
settings.
If the RPM based Fan Speed Control Algorithm is not used, then the PWM duty cycle is updated after
every conversion. It is set to the maximum duty cycle that is stored by the Look Up Table.
The GPIO Direction Register controls the direction of GPIOs 1 and 2.
Bit 1 - GPIO2_DIR - Determines the direction of GPIO2.
Bit 0 - GPIO2_DIR - Determines the direction of GPIO1.
GPIO Direction Register (EMC2103-2 Only)
LUT Temp 4
REGISTER
LUT Temp
Hysteresis
‘0’ (default) - GPIO2 is configured as an input.
‘1’ - GPIO1 is configured as an output.
‘0’ (default) - GPIO1 is configured as an input.
‘1’ - GPIO1 is configured as an output.
Setting 8
GPIO
Direction 1
REGISTER
RPM /
PWM
Table 6.49 Look Up Table Registers (continued)
X
X
-
B7
Table 6.50 GPIO Direction Register
B7
-
-
-
B6
DATASHEET
B6
64
-
B5
65
B5
32
-
B4
B4
16
16
B3
B3
8
8
B2
B2
GPIO
2_DIR
4
4
B1
B1
2
2
Revision 0.85 (01-29-08)
GPIO
1_DIR
B0
B0
1
1
DEFAULT
00h
DEFAULT
(127°C)
0Ah
7Fh