Analog Devices ADT7473 Manual page 71

Table 49. Register 0x79— THERM Timer Status Register (Power-On Default = 0x00)
Bit Name R/W
<7:1> TMR Read-only
<0> Read-only
ASRT/
TMR0
Table 50. Register 0x7A— THERM Timer Limit Register (Power-On Default = 0x00)
Bit Name R/W
<7:0> LIMT Read/write
Table 51. Register 0x7B—TACH Pulses per Revolution Register (Power-On Default = 0x55)
Bit Name R/W
<1:0> FAN1 Read/write
<3:2> FAN2 Read/write
<5:4> FAN3 Read/write
<7:6> FAN4 Read/write
Description
Times the duration THERM input is asserted. These seven bits read 0 until the THERM assertion time
exceeds 45.52 ms.
This bit is set high on the assertion of the THERM input, and is cleared on read. If the THERM assertion time
exceeds 45.52 ms, this bit is set and becomes the LSB of the 8-bit TMR reading. This allows THERM assertion
times from 45.52 ms to 5.82 sec to be reported back with a resolution of 22.76 ms.
Description
Sets maximum THERM assertion length allowed before an interrupt is generated. This is an 8-bit
limit with a resolution of 22.76 ms allowing THERM assertion limits of 45.52 ms to 5.82 sec to be
programmed. If the THERM assertion time exceeds this limit, Bit 5 (F4P) of Interrupt Status Register
2 (Reg. 0x42) is set. If the limit value is 0x00, an interrupt is generated immediately on the assertion
of the THERM input.
Description
Sets number of pulses to be counted when measuring Fan 1 speed. Can be used to determine fan
pulses per revolution for unknown fan type.
Pulses Counted
00 = 1
01 = 2 (default)
10 =
11 = 4
Sets number of pulses to be counted when measuring Fan 2 speed. Can be used to determine fan
pulses per revolution for unknown fan type.
Pulses Counted
00 = 1
01 = 2 (default)
10 = 3
11 = 4
Sets number of pulses to be counted when measuring Fan 3 speed. Can be used to determine fan
pulses per revolution for unknown fan type.
Pulses Counted
00 = 1
01 = 2 (default)
10 = 3
11 = 4
Sets number of pulses to be counted when measuring Fan 4 speed. Can be used to determine fan
pulses per revolution for unknown fan type.
Pulses Counted
00 = 1
01 = 2 (default)
10 = 3
11 = 4
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ADT7473