D12320VF25V Datasheet, PDF (701/1146 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 17 ROM
17.18.2 RAM Overlap
An example in which flash memory block area EB1 is overlapped is shown below.
H'000000
EB0
H'001000
EB1
H'002000
EB2
H'030000
EB3
H'004000
EB4
H'005000
EB5
H'006000
EB6
H'007000
EB7
H'008000
This area can be accessed
from both the RAM area
and flash memory area
Flash memory
EB8 to EB15
On-chip RAM
H'FFDC00
H'FFEBFF
H'07FFFF
H'FFFBFF
Figure 17.49 Example of RAM Overlap Operation
Example in Which Flash Memory Block Area EB1 Is Overlapped
1. Set bits RAMS, RAM2, RAM1, and RAM0 in RAMER to 1, 0, 0, 1, to overlap part of RAM
onto the area (EB1) for which real-time programming is required.
2. Real-time programming is performed using the overlapping RAM.
3. After the program data has been confirmed, the RAMS bit is cleared, releasing RAM overlap.
4. The data written in the overlapping RAM is written into the flash memory space (EB1).
Notes: 1. When the RAMS bit is set to 1, program/erase protection is enabled for all blocks
regardless of the value of RAM2, RAM1, and RAM0 (emulation protection). In this
state, setting the P1 or E1 bit in flash memory control register 1 (FLMCR1), or setting
Rev.7.00 Feb. 14, 2007 page 667 of 1108
REJ09B0089-0700