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I have problem accessing XRAM in DS89C430. I have included startup.A51 file and followed the instruction under forum "http://www.keil.com/support/docs/3345.htm". The issue is when i debug the code all work fine, but when it comes to hardware, i wont get desired data i wrote into XRAM. The code working well with P89V51RD2, but it is required to have faster processing. Please help.
I did not made correction in startup.a51....!!!! Shell i include the code "ORL PMR,#1".
GENERAL for ALL chips with internal XRAM etc: ALSO: for chips with external XRAM where the timings must be changed.
Unless the defaults ("reset states") of the SFR(s) as stated in the datasheet, are what you want you MUST make a local, renamed copy of startup.a51 and include it in your build. In that copy you must at the beginning set all SFRs that affect XRAM addressing.
Not mandatory, but I prefer to, in the same place, to include, if applicable, port configuration, oscillator configuration and other configuration bits affecting the actual functionality if the chip.
Erik
"make a local, renamed copy of startup.a51"
Renaming it is a preference - not mandatory.
Having it local is also a preference (and one that I'd share) - not mandatory.
"at the beginning set all SFRs that affect XRAM addressing"
It doesn't have to be at the beginning - it just needs to be before any XRAM reference that requires it.
Of course, having it at the beginning does guarantee that - but it is not mandatory.