Datasheet ADT7320 (Analog Devices) - 10

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ADT7320 Data Sheet CS DIN 0x08 0x20 WAIT 240ms MINIMUM FOR CONVERSION TO FINISH DATA DOUT SCLK
300 2- 901 0 Figure 12. Typical SPI One-Shot Write to Configuration Register Followed by a Read from the Temperature Value Register
TEMPERATURE 149°C 148°C 147°C TCRIT 146°C 145°C 144°C 143°C 142°C TCRIT – THYST 141°C 140°C CT PIN POLARITY = ACTIVE LOW CT PIN POLARITY = ACTIVE HIGH TIME WRITE TO WRITE TO WRITE TO BIT 5 AND BIT 6 OF BIT 5 AND BIT 6 OF BIT 5 AND BIT 6 OF CONFIGURATION CONFIGURATION CONFIGURATION REGISTER.* REGISTER.* REGISTER.* *THERE IS A 240ms DELAY BETWEEN WRITING TO THE CONFIGURATION REGISTER TO START A STANDARD ONE-SHOT CONVERSION AND THE CT PIN GOING ACTIVE. THIS IS DUE TO THE
013
CONVERSION TIME. THE DELAY IS 60ms IN THE CASE OF A ONE-SHOT CONVERSION.
9012- 0 Figure 13. One-Shot CT Pin
ONE-SHOT MODE CT and INT Operation in One-Shot Mode
When one-shot mode is enabled, the ADT7320 immediately See Figure 13 for more information on one-shot CT pin completes a conversion and then goes into shutdown mode. The operation for TCRIT overtemperature events when one of the one-shot mode is useful when one of the circuit design priorities is limits is exceeded. Note that in interrupt mode, a read from to reduce power consumption. any register resets the INT and CT pins. To enable one-shot mode, set Bits [6:5] of the configuration For the INT pin in comparator mode, if the temperature drops register (Register Address 0x01) to 01. below the THIGH − THYST value or goes above the TLOW + THYST value, a write to the operation mode bits (Bit 5 and Bit 6 of the After writing to the operation mode bits, wait for at least 240 ms configuration register, Register Address 0x01) resets the INT pin. before reading back the temperature from the temperature value register. This delay ensures that the ADT7320 has adequate time For the CT pin in comparator mode, if the temperature drops to power up and complete a conversion. below the TCRIT − THYST value, a write to the operation mode bits (Bit 5 and Bit 6 of the configuration register, Register Address 0x01) To obtain an updated temperature conversion, reset Bits[6:5] of the resets the CT pin (see Figure 13). configuration register (Register Address 0x01) to 01. When using one-shot mode, ensure that the refresh rate is appropriate to the application being used. Rev. 0 | Page 10 of 24 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION PRODUCT HIGHLIGHTS FUNCTIONAL BLOCK DIAGRAM TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS SPI TIMING SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION CIRCUIT INFORMATION CONVERTER DETAILS CONTINUOUS CONVERSION MODE ONE-SHOT MODE CT and INT Operation in One-Shot Mode 1 SPS MODE SHUTDOWN MODE FAULT QUEUE TEMPERATURE DATA FORMAT TEMPERATURE CONVERSION FORMULAS 16-Bit Temperature Data Format 13-Bit Temperature Data Format 10-Bit Temperature Data Format 9-Bit Temperature Data Format REGISTERS STATUS REGISTER CONFIGURATION REGISTER TEMPERATURE VALUE REGISTER ID REGISTER TCRIT SETPOINT REGISTER THYST SETPOINT REGISTER THIGH SETPOINT REGISTER TLOW SETPOINT REGISTER SERIAL INTERFACE SPI COMMAND BYTE WRITING DATA READING DATA INTERFACING TO DSPs OR MICROCONTROLLERS SERIAL INTERFACE RESET INT AND CT OUTPUTS UNDERTEMPERATURE AND OVERTEMPERATURE DETECTION Comparator Mode Interrupt Mode APPLICATIONS INFORMATION THERMAL RESPONSE TIME SUPPLY DECOUPLING POWERING FROM A SWITCHING REGULATOR TEMPERATURE MEASUREMENT QUICK GUIDE TO MEASURING TEMPERATURE OUTLINE DIMENSIONS ORDERING GUIDE