I monitering my I/O port from Peripherials -> I/O-ports -> Port 0 But the value of P0 and Pins are always diferrent That is very strange.. I use P0 as an LCD data bus. I set the value of P0, When I want to display a character on LCD. but Pins bits can't reflect the value of P0 So my LCD display can't work normally. Does any one known what happens? thank you..
Is your P0 configured as an outport port? Are you using the external memory space, in which case P0 is part of the data/address bus?
Thans a lot. I known the bug of uVision simulator. When I set the value of P0(SFR). It's value will not synchronize with PORT0(VTREG). But in real world. The value of P0 is always equas to corresponding Pins. It's a serious bug. I hope keil will correct in next version.
I don't think you really found a bug. First, your assertion that in an actual 8051, the state of the physical port pins and the internal register (P0) simply isn't true. Second, you can have those bits in P0 that are supposed to reflect pin states, i.e. the corresponding bits in the VREG PORT0, react in real-time. Just toggle View->Periodic Window Update.