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Hello,
I'm currently working on the ST10F168 and I'm using the external bus to control some RAMs.
But when I don't use the external RAMs, the external address bus is still changing.
So I would like to know if it's normal, and if it is the same bus which is connected to the external RAMs and to the internal RAM.
If it's the case : if I make an access to an internal address, can the address be seen on the external bus too ?
Thanks.
In general it is not normal but probably you left settings untouched when moved to the no-external-RAM version. Check BUSCON/SYSCON/ADDRSEL registers. Start looking into an *.a?? asm file in your project.
If you have access to internal RAM it does not mean you should see the life on external bus until intentionally use Visible Mode for XBUS peripheral, check SYSCON.
Regards, Nikolay.
I experienced something similar with ST10F168. In my application, a peripheral was connected to the external bus of the MCU. The problem was that after accessing the peripheral, the MCU would not deassert the chip select line. I did not check if the address bus was still active, it probably was. I found a workaround: to deassert CS, I terminated each peripheral access session with an access to on-chip XRAM. Basically, an XBUS access deactivated the external bus, whereas accesses to IRAM did not.
Regards, - mike