PIC24FJ256GU406 memory map

Where everything sits, at its exact address. The PIC24FJ256GU406 keeps program and data apart (modified Harvard). Program memory holds 24-bit instructions and is addressed in program-counter units, two per instruction, so flash ending at 0x02B000 holds 88,064 instructions (258 KB, three bytes each). The data space is 16-bit and byte-addressed: the special function registers at the bottom, then the RAM. Constants in flash are read into data space through the program space visibility window from 0x8000 (PSV, or EDS on the newer chips).

Program memory

Reset and vector table, the program, the configuration words; addresses in program-counter units (two per instruction).

User OTP words0x801700 – 0x8017FF128 words
Configuration words0x2AF00 – 0x2AFFF128 words
Flash0x0000 – 0x2AFFF258 KB (88,064 instructions)

Data memory

16-bit SFRs at the bottom, then the RAM; byte addresses.

RAM0x0800 – 0x7FFF30 KB
Special function registers0x0000 – 0x07FF2 KB

Every segment

SegmentSpaceStartEndSizePage
Special function registersdata0x00000x07FF2 KB
RAMdata0x08000x7FFF30 KB
Flashprog0x00000x2AFFF258 KB (88,064 instructions)
Configuration wordsprog0x2AF000x2AFFF128 words
User OTP wordsprog0x8017000x8017FF128 words