Hitachi H8/3062 Hardware Manual page 524

Single-chip microcomputer

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Flash Memory Emulation in RAM

As flash memory programming and erasing takes time, it may be difficult to carry out tuning by

writing parameters and other data in real time. In this case, real-time programming of flash

memory can be emulated by overlapping part of RAM (H'FFF000–H'FFF3FF) onto a small block

area in flash memory. This RAM area change is executed by means of bits 3 to 1 in the RAM

control register (RAMCR). After the RAM area change, access is possible both from the area

overlapped onto flash memory and from the original area (H'FFF000–H'FFF3FF). For details of

RAMCR and the RAM area setting method, see section 17.3.3, RAM Control Register (RAMCR).

Example of Emulation of Real-Time Flash Memory Programming: In the following example,

RAM area H'FFF000–H'FFF3FF is overlapped onto flash memory area EB2 (H'000800–

Note: * When part of RAM (H'FFF000–H'FFF3FF) is overlapped onto a flash memory small block area, the flash

memory in the overlapped area cannot be accessed. It can be accessed when the overlapping is

Flash memory

Overlapping ram

(Mapping RAM

Figure 17.14 Example of RAM Overlap Operation

1. Part of RAM

3. The programmed data is checked,

4. The data written in RAM area

(H'FFF000–H'FFF3FF) is

overlapped onto the area (EB2)

requiring real-time programming.

(RAMCR bits 3–1 are set to 1, 1, 0,

and the flash memory area to be

overlapped (EB2) is selected.)

Real-time programming is

performed using the overlapping

then RAM overlapping is cleared.

(RAMS bit is cleared.)

H'FFF000–H'FFF3FF is written to

flash memory space.