EMC1813 datasheet(26/102 Pages) MICROCHIP

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5.17

Consecutive Alerts

The EMC1812/13/14/15/33 device family contains multiple consecutive alert counters. One set of

counters applies to the ALERT pin and the second set of counters applies to the THERM pin. Each

temperature measurement channel has a separate consecutive alert counter for each of the ALERT and

THERM pins. All counters are user programmable and determine the number of consecutive

measurements that a temperature channel(s) must be out-of-limit or reporting a Diode Fault before the

corresponding pin is asserted.

The Consecutive Alert register determines how many times an out-of-limit error or Diode Fault must be

detected in consecutive measurements before the ALERT or THERM pin is asserted.

An out-of-limit condition (for example, HIGH, LOW, or FAULT) occurring on the same temperature

channel in consecutive measurements will increment the consecutive alert counter. The counters will also

be reset if no out-of-limit condition or Diode Fault condition occurs in a consecutive reading.

When the ALERT pin is configured as an interrupt and when the consecutive alert counter reaches its

programmed value, the following occurs: the Status bit(s) for that channel and the last error condition(s)

(for example, E1HIGH, or E2LOW and/or E2FAULT) are set to ‘1’, the ALERT pin is asserted, the

consecutive alert counter is cleared and measurements continue to be performed.

When the ALERT pin is configured as a comparator, the consecutive alert counter will ignore Diode Fault

and low limit errors and only increment if the measured temperature exceeds the high limit. Additionally,

once the consecutive alert counter reaches the programmed limit, the ALERT pin is asserted, but the

counter does not reset. It remains set until the temperature drops below the high limit minus the Therm

Hysteresis value.

Channels that are not enabled are not included in the consecutive alert checking. The signal logic chain

is: Limit → Counter → Status → Mask → Pin (THERM and ALERT).

For example, if the CALRT<2:0> bits are set for four consecutive alerts on an EMC1812/13/14/15/33

device, the high limits are set at +70°C and none of the channels are masked, then the ALERT pin is

asserted after the following five measurements:

•

Internal Diode reads +71°C and both the external diodes read +69°C. Consecutive alert counter for

INT is incremented to 1.

•

Both the Internal Diode and the External Diode 1 read +71°C and External Diode 2 reads +68°C.

Consecutive alert counter for INT is incremented to 2 and for EXT1 is set to 1.

•

The External Diode 1 reads +71°C and both Internal Diode and External Diode 2 read +69°C.

Consecutive alert counters for INT and EXT2 are cleared and EXT1 is incremented to 2.

•

The Internal Diode reads +71°C and both external diodes read +71°C. Consecutive alert counter for

INT is set to 1, EXT2 is set to 1 and EXT1 is incremented to 3.

•

The Internal Diode reads +71°C and both external diodes read +71°C. Consecutive alert counter for

INT is incremented to 2, EXT2 is set to 2 and EXT1 is incremented to 4. The appropriate Status bits

are set for EXT and the ALERT pin is asserted. EXT1 counter is reset to 0 and all other counters

hold the last value until the next temperature measurement.

All temperature channels use this value to set the respective counters. The consecutive Therm counter is

incremented whenever any measurement exceeds the corresponding Therm limit.

If the temperature drops below the Therm limit, the counter is reset. If a number of consecutive

measurements above the Therm limit occurs, the THERM pin is asserted low.

Multi-Channel Low-Voltage Remote Di...

System Block Diagram

Datasheet

DS20005751A-page 26

EMC1813 Datasheet(PDF) 26 Page - Microchip Technology

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