m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 414

• Manufacturer Part Number: m37905
• Description: Mitsubishi 16-bit Single-chip Microcomputer 7700 Family / 7900 Series
• Manufacturer: Renesas Electronics Corporation.

(3) Flash memory reset bit (bit 3)
(4) User ROM area select bit (bit 5)
Writing “1” to this bit discontinues the access to the user ROM area and causes the built-in flash
memory control circuit to be reset. After this reset, the microcomputer enters the read array mode to
set the RY/BY status bit (bit 0) to “1”.
When this flash memory control circuit is reset with the flash memory reset bit during programming
(automatic programming) or erase (automatic erase) operation, that programming or erase operation
is discontinued to invalidate the data in the working block.
After writing of “1” to this bit, be sure to confirm the RY/BY status bit (bit 0) becomes “1”; and then,
write “0” to this bit.
This bit is used to select either the boot ROM area or the user ROM area in the boot mode. In order
to access the boot ROM area (read out), clear this bit to “0.” On the other hand, in order to access
the user ROM area (reading out, programming, or erase), set it to “1.” Instructions for writing into this
bit must be executed in an area other than the internal flash memory (e.g. the internal RAM area).
Note that when MD1 = Vss level, the user ROM area is accessed (being read out) regardless of the
contents of this bit.
7905 Group User’s Manual Rev.1.0
19.2 Flash memory CPU reprogramming mode
FLASH MEMORY VERSION
19-11