AN2267

Implementation using ST7FMC

9/19

Figure 9.

Update (U) event interrupt subroutine flow chart

The flowchart in Figure 9 shows the actions within the U event interrupt service routine. To

coordinate the reading of any other analog inputs to the ADC, it is recommended that they

are all read within this U event subroutine after the DC link current read. However, before

returning from the interrupt, it is important to restore the ADC to sample the DC link current

channel again so that on re-entry in the next U event, the DC link current value can be read

from ADC right away. If required, interrupt priority of this routine can be lowered after

reading the current value upon entry, but should be restored to the highest value before

returning for obvious reasons.

Refer to the accompanying file for a complete listing of the code and experimental

workspace.

Start U

Read current feedback

Set U ISR priority lower if required

Read other Analog inputs

Current loop PI regulator

Dutycycle update

Set ADC Channel back to Sample current feedback

Restore ISR priority to the highest

End U