MAX1617A Datasheet, PDF (17/18 Pages) Maxim Integrated Products – Remote/Local Temperature Sensor with SMBus Serial Interface

Remote/Local Temperature Sensor
with SMBus Serial Interface
Listing 1. Pseudocode Example (continued)
Programming Example:
Clock-Throttling Control for CPUs
Listing 1 gives an untested example of pseudocode for
proportional temperature control of Intel mobile CPUs
via a power-management microcontroller. This program
consists of two main parts: an initialization routine and
an interrupt handler. The initialization routine checks for
SMBus communications problems and sets up the
MAX1617A configuration and conversion rate. The
interrupt handler responds to ALERT signals by reading
the current temperature and setting a CPU clock duty
factor proportional to that temperature. The relationship
between clock duty and temperature is fixed in a look-
up table contained in the microcontroller code.
Note: Thermal management decisions should be made
based on the latest temperature obtained from the
MAX1617A rather than the value of the Status Byte. The
MAX1617A responds very quickly to changes in its
environment due to its sensitivity and its small thermal
mass. High and low alarm conditions can exist in the
Status Byte due to the MAX1617A correctly reporting
environmental changes around it.
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