In order for PIC to issue an interrupt, GIEH (Global Interrupt Enable, High priority) must be enabled among other things. This seems logical, looking at interrupt logic scheme. However, should this bit be changed during interrupt function?
According to one source, GIEH is only set (GIEH = 1) in the main function and left unchanged. However, according to some other source, GIEH is also set in main function, but when interrupt function starts, it is cleared (GIEH = 0) and before this function ends, GIEH is set.
Should GIEH be altered during interrupt function (for some reason)?
Keno