hi,
due my new project I prepare myself to use DataFlash^(R) from Atmel together with AT89C51CC03. The problem is that the Flash works at 3.0V while MCU must still be supplied with 5V. I know enough about "level shifter" ICs and I have planed to use it; nevertheless I have one idea I do not know is it usable or not.
You see, for MCU I`ll use software emulated (here: no MOVX but manipulate with bus/bits manually instead) Rapid8 interface of AT45DB642. Rapid8 has 8-bit data bus. It will be connected to P0 of MCU. As you know, P0 is open drain one and so I think: is it necessary to use level shifter for it too? The idea is to connect P0 and IO0...IO8 of AT45DB642 directly with pullup resistors to 3V. From one side both MCU and Flash will be able to produce low level here; from other side, MCU produces high level via open drain + pullup resistors and accepts it as 2,8V which is enough to be recognized as "1" as well.
So what do you think: is it correct to use such connection scheme or better to use bidir level shifter, like 74LVC4245A etc?

Thanks,
Oleg