TMP89FS60 datasheet(322/410 Pages) TOSHIBA

322 / 410 page

Page 308

21. Flash Memory

TMP89FS60

RA003

21.2.2 Flash memory area switching (FLSCR1<FAREA>)

To perform an erase or write on the flash memory, a memory transfer instruction (command sequence) must

be executed. If a memory transfer instruction is used to read or write data, a read or write can be performed

only on the data area. To perform an erase or write on the code area, therefore, part of the code area must be

temporarily switched to the data area. This switching between data and code areas is performed by making the

appropriate FLSCR1<FAREA> setting.

By setting "0xD5" on FLSCR2<CR1EN> after setting FLSCR1<FAREA> to "10", 0x8000 through 0xFFFF

(AREA C1) in the code area is mapped to 0x8000 through 0xFFFF (AREA D1) in the data area.

To restore the flash memory to the initial state of mapping, set FLSCR1<FAREA> to "00", and then set

"0xD5" on FLSCR2<CR1EN>.

All flash memory areas can be accessed by performing the appropriate steps described above and then exe-

cuting the memory transfer instruction on 0x8000 through 0xFFFF (AREA D1) in the data area.

Additionally, access to areas to which memory is not assigned should be avoided by executing an instruction

or specifying such an area by using jump or call instructions.

By setting "0xD5" on FLSCR2<CR1EN> after setting FLSCR1<FAREA> to "01", 0x1000 through 0x7FFF

(AREA D0) in the data area is mapped to 0x9000 through 0xFFFF (AREA D1) in the data area.

By setting "0xD5" on FLSCR2<CR1EN> after setting FLSCR1<FAREA> to "11", 0x1000 through 0x7FFF

(AREA C0) in the code area is mapped to 0x9000 through 0xFFFF (AREA D1) in the data area.

For example, to access 0x4000 in the code area, set "0xD5" on FLSCR2<CR1EN> after setting

FLSCR1<FAREA> to "10", and then execute the memory transfer instruction on 0xC000.

0x1000 through 0xFFFF (AREA D1) in the data area and 0x1000 through 0xFFFF (AREA C1) in the code

area are mirror areas; these two areas refer to the same physical address in memory. Therefore, an erase or write

must be performed on one of these two mirror areas. For example, If a write is performed on 0x8000 in the data

area with FLSCR1<FAREA> set to "10" after performing a write on 0x8000 in the data area with

FLSCR1<FAREA> set to "00", data is overwritten. To write data to the flash memory that already has data writ-

ten to it, existing data must first be erased from the flash memory by performing a sector erase or chip erase, and

then data must be written.

TMP89FS60 Datasheet(PDF) 322 Page - Toshiba Semiconductor