MOV R0,R0 will give a syntax error at assemble-time because there are no instructions that can move one "R" register directly into another "R" register. This is a limitation of the instruction set which the assembler correctly enforces.

The weird thing about MOV A,ACC not working is that the code CAN be assembled and it is being suggested that even though it will assemble and produce correct and logical machine code, the MCU considers it invalid.

Another interesting issue would be if MOV A,ACC is considered invalid, is MOV ACC,A also considered invalid? The two instructions will produce different machine code...

Does anyone have any technical contacts at Philips? Perhaps a quick Q&A directly to Philips would be the fastest and most reliable way to resolve this question.

Craig Steiner