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Hello!
We have a DS80C400 based system. We have a CPLD which has chip-select based on some Address lines and PCE0#. The CPLD uses RD# and WR# lines instead of PSEN# and WR#.
We have configured the MCU to use PCE0-3# as PCE lines (instead of I/O) and Address lines A16-A21 to be generated automatically.
We are trying to access 0x100000 (A20 is HIGH) using the FVAR(unsigned char, 0x100000). However, the PCE0# is not getting asserted (it is at HIGH always).
ANy solution in mind? Please contact me for further info. Also, Thanks in Advance!!
Thanks & BR, Govinda Padaki
Hi,
Drew is right concerning the macros for FVAR.
As for access on the DS80C400, assuming you use the 'typical' external memory access of this CPU, you will not need to worry about any 'extra' time'.
Assuming you choose to use the Dallas C libraries (and why not, they're free and reasonably good), you will have the hardware configured for 24 bit memory access, so a FAR memory access is as efficient as an XDATA one.
You should not have to worry about, or look at, the XBANKING.A51 or L51_BANK.A51 files.