ADT7466
Rev. 2 | Page 36 of 48 | www.onsemi.com
REGISTER DETAILS
Configuration 1
Table 31. Register 0x00—Configuration Register 1 (Power-On Default = 0x01)
Bit No. Name Read/Write Description
0 STRT Read/Write Logic 1 enables monitoring, and PWM control outputs based on the limit settings programmed.
Logic 0 disables monitoring and PWM control based on the default power-up limit settings. The limit
values programmed are preserved even if a Logic 0 is written to this bit and the default settings are
enabled. This bit becomes read only and cannot be changed once Bit 1 (LOCK bit) is written. All limit
registers should be programmed by BIOS before setting this bit to 1. Lockable.
1 LOCK Write Once Logic 1 locks all limit values to their current settings. Once this bit is set, all lockable registers become
read only and cannot be modified until the ADT7466 is powered down and powered up again. This
prevents rogue programs such as viruses from modifying critical system limit settings. Lockable.
2 RDY Read Only This bit is set to 1 by the ADT7466 to indicate that the device is fully powered up and ready to begin
systems monitoring.
3 FSPD Read/Write When this bit is 1, it runs all fans at full speed. Power-on default is 0. This bit is not locked at any time.
4 FSPDIS Read/Write Logic 1 disables fan spin-up for two tach pulses. Instead, the DAC outputs go high for the entire fan
spin-up timeout selected.
5 TODIS Read/Write When this bit is 1, the SMBus timeout feature is disabled. This allows the ADT7466 to be used with
SMBus controllers that cannot handle SMBus timeouts. Lockable.
6 V
CC
Read/Write When this bit is 1, the ADT7466 rescales its V
CC
pin to measure a 5 V supply.
When this bit is 0, the ADT7466 measures V
CC
as a 3.3 V supply. Lockable.
7 OBIN Read/Write When this bit is 0 (default) temperature data format is binary.
When this bit is 1, format is offset binary.
Configuration 2
This register becomes read only when the Configuration Register 1 lock bit is set to 1. Additional attempts to write to this register have no
effect.
Table 32. Register 0x01—Configuration Register 2 (Power-On Default = 0x00)
Bit No. Name Read/Write Description
0 RTYPE Read/Write When this bit is cleared (default), thermistor normalization is optimized for 100 kΩ thermistors. When
this bit is set, it is optimized for 10 kΩ thermistors.
1 CURR Read/Write This bit sets the thermal diode current. It should be left at 0.
2 REFZ Read/Write Setting this bit makes the REFOUT pin high impedance.
3 Unused – Unused. Write ignored. Reads back 0.
4 AVG Read/Write When AVG is 1, averaging on the temperature and voltage measurements is turned off. This allows
measurements on each channel to be made much faster.
5 RATE Read/Write If averaging is turned off and measurement set to single channel mode, the RATE bit sets the
conversion rate. 0 = 32 conversions/second; 1 = 4 conversions/second.
6 SHDN Read/Write When SHDN is 1, the ADT7466 goes into shutdown mode. Both DAC outputs are set to 0 V to switch off
both fans. The DAC registers read back 0x00 to indicate that the fans are not being driven.
7 REM2 Read/Write Setting this bit configures AIN1 and AIN2 for connection of a second thermal diode. Setting this bit
overrides THER1 and THER2 in Configuration Register 3.
