emc2105 Standard Microsystems Corp., emc2105 Datasheet - Page 55

• Manufacturer Part Number: emc2105
• Description: Emc2105 Rpm-based High Side Fan Controller With Hardware Thermal Shutdown
• Manufacturer: Standard Microsystems Corp.

ADDR
ADDR
27h
28
RPM-Based High Side Fan Controller with Hardware Thermal Shutdown
Datasheet
SMSC EMC2105
R/W
R/W
6.13.1
6.14
6.15
R/W
R-C
REGISTER
Interrupt
REGISTER
Enable
Fan Status
Register
Tcrit Status Register
The Tcrit Status Register stores the event that caused the SYS_SHDN# pin to be asserted. Each of
the temperature channels must be associated with the SYS_SHDN# pin before they can be set (see
Section
below the threshold level however the individual status bit will not be cleared until read.
Bit 7 - HWS - This bit is set if the hardware set temperature channel meets or exceeds the temperature
threshold determined by the TRIP_SET voltage.
The Fan Status Register contains the status bits associated with each fan driver. This register is
cleared when read if the error condition has been removed.
Bit 7 - WATCH - This bit is asserted ‘1’ if the host has not programmed the fan driver within four (4)
seconds after power up.
Bit 6 - DRIVE_FAIL - Indicates that the RPM based Fan Speed Control Algorithm cannot drive the Fan
to the desired target setting at maximum drive. This bit can be masked from asserting the ALERT# pin.
Bit 5 - FAN_SHORT - This bit is asserted ‘1’ if the High Side Fan Driver detects an over current
condition that lasts for longer than 2 seconds.
Bit 1- FAN_SPIN- This bit is asserted ‘1’ if the Spin up Routine for the Fan cannot detect a valid
tachometer reading within its maximum time window. This bit can be masked from asserting the
ALERT# pin.
Bit 0 - FAN_STALL1 - This bit is asserted ‘1’ if the tachometer measurement on the Fan detects a
stalled fan. This bit can be masked from asserting the ALERT# pin.
The Interrupt Enable Register controls the masking for each temperature channel. When a channel is
masked, it will not cause the ALERT# pin to be asserted when an error condition is detected.
Bit 5 - VOLT4_INT_EN - Allows the Voltage Input 4 channel to assert the ALERT# pin.
Fan Status Register
Interrupt Enable Register
‘0’ - The RPM based Fan Speed Control Algorithm can drive the Fan to the desired target setting.
‘1’ - The RPM based Fan Speed Control Algorithm cannot drive the Fan to the desired target setting
at maximum drive.
‘0’ (default) - The ALERT# pin will be not be asserted for any error condition associated with
Voltage Channel 4 (TRIP_SET / VIN4).
6.8). Once the SYS_SHDN# pin is asserted, it will be released when the temperature drops
WATCH
B7
-
B7
B6
Table 6.20 Interrupt Enable Register
-
B6
Table 6.19 Fan Status Register
-
VOLT4_I
NT_EN
DATASHEET
DRIVE
_FAIL
B5
B5
55
SHORT
EXT4_I
NT_EN
FAN_
B4
B4
EXT3_I
NT_EN
B3
B3
-
EXT2_I
NT_EN
B2
B2
-
EXT1_I
NT_EN
Revision 1.74 (05-08-08)
FAN_
SPIN
B1
B1
INT_IN
STALL
T_EN
FAN_
B0
B0
DEFAULT
DEFAULT
00h
00h