Datasheet ADT7408 (Analog Devices) - 10

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ADT7408 Data Sheet REGISTERS
The ADT7408 contains 16 accessible registers, shown in Table 5.
ADDRESS POINTER REGISTER (WRITE ONLY)
The address pointer register is the only register that is eight bits; the other registers are 16 bits wide. On power-up, the address This 8-bit write only register selects which of the 16-bit registers pointer register is loaded with 0x00 and points to the capability is accessed in subsequent read/write operations. Address space register. between 0x08 and 0x0F is reserved for factory usage.
Table 5. Registers MSB LSB D7 D6 D5 D4 D3 D2 D1 D0 Pointer Power-On Address Register Name Default Read/Write
0 0 0 0 Register Register Register Register select select select select Not Applicable Address pointer 0x00 Write 0x00 Capability 0x001D Read 0x01 Configuration 0x0000 Read/Write
Table 6. Address Pointer Selected Registers
0x02 Alarm 0x0000 Read/Write
D2 D1 D0 Register Selected
temperature upper boundary 0 0 0 Capability trip 0 0 1 Configuration 0x03 Alarm 0x0000 Read/Write 0 1 0 Alarm temperature upper boundary trip temperature 0 1 1 Alarm temperature lower boundary trip lower boundary 1 0 0 Critical temperature trip trip 1 0 1 Temperature value 0x04 Critical 0x0000 Read/Write 1 1 0 Manufacturer ID temperature trip 1 1 1 Device ID/revision 0x05 Temperature value Undefined Read 0x06 Manufacturer ID 0x11D4 Read
CAPABILITY REGISTER (READ ONLY)
0x07 Device ID/revision 0x080X Read 0x08 to 0x0F Vendor defined 0x0000 Reserved This 16-bit, read-only register indicates the capabilities of the thermal sensor, as shown in Table 7 and the following bit map. Note that RFU means reserved for future use.
MSB LSB D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
RFU RFU RFU RFU RFU RFU RFU RFU RFU RFU RFU TRES1 TRES0 Wider Higher Alarm/critical range precision trips
Table 7. Capability Mode Description Bit(s) Function
D0 Basic capability. (Alarm/Critical Trips)
D0 Trips Capability
1 Alarm and critical trips capability. D1 Accuracy. (Higher Precision)
D1 Accuracy Capability
0 Default accuracy ±2°C over the active range and ±3°C over the monitor range. D2 Wider range. (Wider Range)
D2 Temperature Range Capability
1 Can read temperature below 0°C and set sign bit accordingly (default). [D4:D3] Temperature resolution. (Temperature Resolution)
[D4:D3] Temperature Resolution
01 0.25°C LSB. 11 0.0625°C LSB (default). [D15:D5] Reserved for future use; must be 0. Rev. A | Page 10 of 22 Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING CHARACTERISTICS TIMING DIAGRAM ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION CIRCUIT INFORMATION CONVERTER DETAILS MODES OF OPERATION REGISTERS ADDRESS POINTER REGISTER (WRITE ONLY) CAPABILITY REGISTER (READ ONLY) CONFIGURATION REGISTER (READ/WRITE) TEMPERATURE TRIP POINT REGISTERS Alarm Temperature Upper Boundary Trip Register (Read/Write) Alarm Temperature Lower Boundary Trip Register (Read/Write) Critical Temperature Trip Register (Read/Write) Temperature Value Register (Read Only) ID REGISTERS Manufacturer ID Register (Read Only) Device ID and Revision Register (Read Only) TEMPERATURE DATA FORMAT 12-Bit Temperature Data Format 10-Bit Temperature Data Format EVENT PIN FUNCTIONALITY Event Thresholds Alarm Window Trip Critical Trip Interrupt Mode Comparator Mode SERIAL INTERFACE Serial Bus Address SMBUS/I2C COMMUNICATIONS Writing Data to a Register Reading Data From the ADT7408 Writing to the Pointer Register for a Subsequent Read Reading from Any Pointer Register APPLICATIONS INFORMATION THERMAL RESPONSE TIME SELF-HEATING EFFECTS SUPPLY DECOUPLING TEMPERATURE MONITORING OUTLINE DIMENSIONS ORDERING GUIDE