I've never found anywhere if this is the correct value ? (+1, but
it could be +2 per access, or +3, ...)
Can you confirm this +1 per extra access to external memory ?
To the best of my knowledge it is +1 per serialised external reference, so a maximum of +2.
I noticed a section on this in the DSP family manual so it can be double checked against that if necessary (it does seem like it could be +1 'instruction cycles' or +2 oscillator cycles but I don't think so... the manuals always speak in terms of oscillator cycles...).
D.