DS1821

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PROGRAMMING COMMAND FUNCTIONS

The command set for the DS1821 as shown in Table 2 is as follows:

Read Temperature [AAh]

This command reads the contents of the register which contains the last temperature conversion result.

Write TH [01h]

This command writes to the TH (HIGH TEMPERATURE) register. After issuing this command, the user

writes 8 bits of data to the TH register.

Write TL [02h]

This command writes to the TL (LOW TEMPERATURE) register. After issuing this command, the user

writes 8 bits of data to the TL register.

Read TH [A1h]

This command reads the value of the TH (HIGH TEMPERATURE) register. After issuing this command,

the user reads the 8 bits of data present in the TH register.

Read TL [A2h]

This command reads the value of the TL (LOW TEMPERATURE) register. After issuing this command,

the user reads the 8 bits of data present in the TL register.

Write Status [0Ch]

This command writes to the status register. This would be used for clearing the values of the THF and

bit data into the register.

Read Status [ACh]

This command reads the value in the status register. After issuing this command, the user reads the 8 bits

present in the status register.

Start Convert T [EEh]

This command begins a temperature conversion. No further data is required. In One-Shot mode, the

temperature conversion will be performed and then the DS1821 will remain idle. In continuous mode, this

command will initiate continuous conversions.

Stop Convert T [22h]

This command stops temperature conversion. No further data is required. This command may be used to

halt a DS1821 in continuous conversion mode. After issuing this command, the current temperature

measurement will be completed, and then the DS1821 will remain idle until a Start Convert T is issued to

resume continuous operation.