HD64F3048VTF8 Datasheet, PDF (609/903 Pages) Renesas Technology Corp – Hardware Manual Renesas 8-Bit Single-Chip

Section 18 ROM (H8/3048F-ONE: Single Power Supply, H8/3048B Mask ROM Version)
18.2.4 Flash Memory Emulation in RAM
In the H8/3048F-ONE, flash memory programming can be emulated in real time by overlapping
the flash memory with part of RAM (“overlap RAM”). When the emulation block set in RAMCR
is accessed while the emulation function is being executed, data written in the overlap RAM is
read. Emulation should be performed in user mode or user program mode.
Flash memory
Emulation block
SCI
RAM
Application program
Execution state
Overlap RAM
(emulation is performed
on data written in RAM)
Figure 18.3 Reading Overlap RAM Data in User Mode or User Program Mode
When overlap RAM data is confirmed, clear the RAMS bit to release RAM overlap, and actually
perform writes to the flash memory.
When the programming control program is transferred to RAM in on-board programming mode,
ensure that the transfer destination and the overlap RAM do not overlap, as this will cause data in
the overlap RAM to be rewritten.
Rev. 3.00 Sep 27, 2006 page 581 of 872
REJ09B0325-0300