D12320VF25V Datasheet, PDF (607/1146 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 17 ROM
17.4.3 Flash Memory Operating Modes
Mode Transitions: When the mode pins and the FWE pin are set in the reset state and a reset-
start is executed, the chip enters one of the operating modes shown in figure 17.3. In user mode,
flash memory can be read but not programmed or erased.
Flash memory can be programmed and erased in boot mode, user program mode, and programmer
mode.
MD1 = 1,
MD2 = 1,
FWE = 0
User mode
(on-chip ROM
enabled)
RES = 0
RES = 0
FWE = 1,
SWE = 1
FWE = 0
or SWE = 0
User
program mode
Reset state
FWE = 1,
MD1 = 1,
MD2 = 0
*
RES = 0
RES = 0
Programmer mode
On-board programming mode
Boot mode
Notes: Only make a transition between user mode and user program mode when the CPU is
not accessing the flash memory.
* MD2 = MD1 = MD0 = 0, PF2 = 1, PF1 = PF0 = 0
Figure 17.3 Flash Memory Mode Transitions
Rev.7.00 Feb. 14, 2007 page 573 of 1108
REJ09B0089-0700