7906 datasheet(388/531 Pages) RENESAS

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FLASH MEMORY VERSION

7906 Group User’s Manual Rev.2.0

19-11

19.2 Flash memory CPU reprogramming mode

(3) Flash memory reset bit (bit 3)

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.

(4) User ROM area select bit (bit 5)

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.

7906 Datasheet(PDF) 388 Page - Renesas Technology Corp