Software routines

AN2288

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5.3

Lite timer time base2 interrupt routine

This routine is the heart of the MCU, which is generated after every 200µs. This means with

a 50Hz sinewave the number of samples per cycle is 100. In this interrupt routine, the

voltage and current samples are taken by changing the active channel for ADC. One current

sample is taken in between the two voltage sample. The two voltage samples are taken to

minimize the error due to a shift in sampling time for voltage and current sample.

Multiplication and accumulation of V*I is done separately for each current gain.

Figure 17. Lite timer interrupt routine

LT_TB2_IT_Routine

Is AVDF flag=0 &

AVD_INTERRUPT =

Disabled?

yes

Enable AVD interrupt

no

Clear TimeBase2

interrupt Flag

EnableInterrupts

Read first Voltage Sample

Read Curent Sample

Read Second Voltage Sample

Average V1 and V2

A