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Code limit exceeding 64KB

Can anybody say how to interface the EPROM(64KB) with P89c51RD2HBP so that when the code limit exceeds 64KB in the philips controller the exceeded segment should goto the EPROM.

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  • In addition to what Andy has posted
    You should also consider whether this is an indication that the P89c51RD2HBP is the wrong chip for the job
    In all (non-forum) cases where I have been asked about code banking the solution has been NOT to use code banking, but to write better code. A typical request for code banking will be combined with "we use the LARGE model" or some such.

    Once you go for code banokng the process will snowball, first you lose 16 port pins (and - most likely have to make some MMIO) which again increases your code size, then you will find other areas where the effect of banking result in growth.

    BTW why use a discontinued chip the Rx2H has been discontinued for, at least, two years.

    If you insist on using bloated code and banking you will, with the P89c51RD2HBP need to have ALL code memory external, since the !EA is latched on power up.

    Erik

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  • In addition to what Andy has posted
    You should also consider whether this is an indication that the P89c51RD2HBP is the wrong chip for the job
    In all (non-forum) cases where I have been asked about code banking the solution has been NOT to use code banking, but to write better code. A typical request for code banking will be combined with "we use the LARGE model" or some such.

    Once you go for code banokng the process will snowball, first you lose 16 port pins (and - most likely have to make some MMIO) which again increases your code size, then you will find other areas where the effect of banking result in growth.

    BTW why use a discontinued chip the Rx2H has been discontinued for, at least, two years.

    If you insist on using bloated code and banking you will, with the P89c51RD2HBP need to have ALL code memory external, since the !EA is latched on power up.

    Erik

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