Post by thread:Memory pages

Hi there, I'm busy writibg code that is going to overflow into the second page of program memory. Does this mean anything significant. What are the differences in the second memory page. Also I have many variable in the second page of file register memory. Do I need to change the page to read/write to these registers?? Thanks in advance Norman

Hi everyone, I am moving from a 16c55 to a 57 because of memory sortage. My problem is that i don't understand how to use file registers when the program is running in page 1, 2, or 3. I've read the following in a text book but i don't really understand much. Could someone help ?? "If a page in RAM is crossed and registers need to be addressed, remember to drop the first digit of the address ie in the 16Cxx the option register is address 81H. When working in page 1, the actual address is 01H, of that page." Thanks in advance. Harry Tenopoulos MSc - RTES University of Bradford

Harry: The item you quoted does not apply to the 16C5x (16C5x is not a subset of 16Cxx). Page selection is independent for ROM and RAM. Program memory is page selected by the RP bits in the status register. These must be preset before modifying the program counter with a CALL, GOTO, or arithmetic operation with PC as the destination. Bank selection in RAM is controlled by bits 5 and 6 in the fsr. Any access, not just via indf, to file registers 0x10 and up will be to the file register bank indicated by these bits. - Mark Sullivan -