ADM1027ARQZ-RL71 ONSEMI [ON Semiconductor], ADM1027ARQZ-RL71 Datasheet - Page 42

• Manufacturer Part Number: ADM1027ARQZ-RL71
• Manufacturer: ONSEMI [ON Semiconductor]

ADM1027
Register Address
0x20
0x21
0x22
0x23
0x24
If the extended resolution bits of these readings are also being read, the extended resolution registers (Reg. 0x76, 0x77) should be read
first. Once the extended resolution register is read, the associated MSB reading registers are frozen until read. Both the extended
resolution register and the MSB registers are frozen.
Register Address
0x25
0x26
0x27
These temperature readings are in twos complement format.
*Note that a reading of 0x80 in a temperature reading register indicates a diode fault (open or short) on that channel. If the extended resolution bits of these readings
Register Address
0x28
0x29
0x2A
0x2B
0x2C
0x2D
0x2E
0x2F
These registers count the number of 11.11 ms periods (based on an internal 90 kHz clock) that occur between a number of consecutive
fan tach pulses (default = 2). The number of tach pulses used to count can be changed using the fan pulses per revolution register
(Reg. 0x7B). This allows the fan speed to be accurately measured. Since a valid fan tachometer reading requires that two bytes are
read; the low byte MUST be read first. Both the low and high bytes are then frozen until read. At power-on, these registers contain
0x0000 until such time as the first valid fan tach measurement is read in to these registers. This prevents false interrupts from occurring
while the fans are spinning up.
A count of 0xFFFF indicates that a fan is:
are also being read, the extended resolution registers (Reg. 0x76, 0x77) should be read first. Once the extended resolution register is read, all associated MSB reading
registers are frozen until read. Both the extended resolution register and the MSB registers are frozen.
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
R/W
R/W
R/W
Table VII. Fan Tachometer Reading Registers (Power-On Default = 0x00)
Table VI. Temperature Reading Registers (Power-On Default = 0x80)
Table V. Voltage Reading Registers (Power-On Default = 0x00)
2.5 V Reading (8 MSBs of reading).
5 V Reading (8 MSBs of reading).
12 V Reading (8 MSBs of reading).
Remote 1 Temperature Reading* (8 MSBs of reading).
Local Temperature Reading (8 MSBs of reading).
Remote 2 Temperature Reading* (8 MSBs of reading).
TACH1 Low Byte
TACH1 High Byte
TACH2 Low Byte
TACH2 High Byte
TACH3 Low Byte
TACH3 High Byte
TACH4 Low Byte
TACH4 High Byte
Description
V
V
Description
Description
CCP
CC
Reading. Measures V
1. Stalled or Blocked (object jamming the fan)
2. Failed (internal circuitry destroyed)
3. Not Populated (The ADM1027 expects to see a fan connected to
4. 2-Wire Instead of 3-Wire Fan
Reading. Holds processor core voltage measurement (8 MSBs of reading).
Rev. 3 | Page 42 of 56 | www.onsemi.com
each TACH. If a fan is not connected to that TACH, its TACH
minimum high and low bytes should be set to 0xFFFF.)
–42–
CC
through the V
CC
pin (8 MSBs of reading).
REV. A