HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 621

• Manufacturer Part Number: HD6433044
• Description: (HD64 Series) Hitachi Single-Chip Microcomputer
• Manufacturer: Hitachi Semiconductor

Example of Emulation of Real-Time Flash-Memory Update
Small-block
area (SB5)
Notes: 1. When part of RAM (H'FFF000 to H'FFF1FF) is overlapped onto a small-block area in flash
2. When the RAMS bit is set to 1, all flash memory blocks are write-protected and erase-
memory, the overlapped flash memory area cannot be accessed. Access is enabled when
the overlap is cleared.
protected, regardless of the values of bits RAM2 to RAM0. In this state, no transition to
program or erase mode will take place if the P or E bit is set in the flash memory control
register (FLMCR). To actually program or erase a flash memory area, the RAMS bit must
be cleared to 0.
H'01F000
H'01F9FF
H'01FA00
H'01FBFF
H'01FDFF
H'01FE00
H'01FFFF
address space
Flash memory
Figure 18-20 Example of RAM Overlap
H'FFEF10
H'FFF000
H'FFF1FF
H'FFF200
H'FFFF0F
Overlapped by RAM
On-chip RAM
612
area
Procedure
1. Set the RAME bit to 1 in SYSCR
2. Overlap part of RAM (H'FFF000 to
3. Perform real-time updates in the
4. After finalization of the update
5. Program the data written in RAM
to enable the on-chip RAM.
H'FFF1FF) onto the area requiring
real-time update (SB5).
(Set RAMCR bits 3 to 0 to 1101.)
overlapping RAM.
data, clear the RAM overlap (by
clearing the RAMS bit).
addresses H'FFF000 to H'FFF1FF
into the flash memory area.