To be honest, I'm not sure why all the dancing around the subject of PDATA except that it proves to be one of those simple, but difficult to explain, concepts.

On the E5, you can use PDATA just as you would with any other 8051/52 device. However, there is one 'gotcha' to watch out for under a very specific condition.

IFF ...

* you are using indirect addressing to access XDATA (MOVX A, @Ri), and

* you "exported" P2 as an 8051-style PIO port. Exporting is a Triscend capability where you can take any one of the 8051's SFRs (and even those that don't exist on an 8051) and "export" them out into the E5's programmable logic array. Ideal for making your own custom peripherals!

I'll dig up the details and post them separately but the gotcha only shows its ugly head under these very specific and rare conditions on the E5. Fortunatley, even if you run into this 'gotcha', there are plenty of work-arounds.