Rohm LAPIS SEMICONDUCTOR ML620Q503, User Manual

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ML620Q503/Q504 User's Manual
Chapter 27 Flash Memory Control
FEUL620Q504 27- 11
27.3.2 Data Flash Rewriting
The LSI is equipped with a data flash of 2 KB (2 sectors: 1 KB/sector). The rewrite count is 10,000.
Figure 27-1 shows the sequence of 1-word write/sector erase/block erase.
Writing is performed sequentially from the first sector. When writing to the second sector is saturated, the first sector is
erased, and the next data is written to it. Thus, up to 1024 * 10,000 times of rewrite is realized when data is written by
one word.
As the initial value after an erase is "FFFFH", the position matching the initial value is searched for as the write position.
Figure 27-1 Data Flash Rewrite Sequence
27.3.3 Program Memory Rewrite (ISP Function)
The program can be rewritten by software by using the ISP function. There are the following two ways to execute the
ISP program:
1) Execute the program by remapping the boot area of the ISP program by software
2) Execute the program by remapping the ISP boot area by hardware at LSI startup
These methods boot the ISP program and rewrite the program memory in the same sequence as the data flash rewrite.
These remap methods is as follows.
Set "1” to FSELF
Set "FA” and "F5” in this order to FLASHACP
Set address to FLASHSEG and FLASHA
Set data to FLASHD
Read/compare from CPU
Any other address
processing?
yes
no
Set "1” to FSERS Set "1” to FERS
Set "0” to FSELF
(For 1-word write)
(For sector erase) (For block erase)
(*)
*: The CPU stops during the write/erase processing. Perform the NOP processing twice after this processing.