R28 datasheet(362/473 Pages) RENESAS

362 / 473 page

R8C/28 Group, R8C/29 Group

19. Flash Memory

Rev.2.10

Sep 26, 2008

Page 343 of 441

REJ09B0279-0210

19.3

Functions to Prevent Rewriting of Flash Memory

Standard serial I/O mode has an ID code check function, and parallel I/O mode has a ROM code protect function to

prevent the flash memory from being read or rewritten easily.

19.3.1

ID Code Check Function

This function is used in standard serial I/O mode. Unless the flash memory is blank, the ID codes sent from the

programmer and the ID codes written in the flash memory are checked to see if they match. If the ID codes do

not match, the commands sent from the programmer are not acknowledged. The ID codes consist of 8 bits of

data each, the areas of which, beginning with the first byte, are 00FFDFh, 00FFE3h, 00FFEBh, 00FFEFh,

00FFF3h, 00FFF7h, and 00FFFBh. Write programs in which the ID codes are set at these addresses and write

them to the flash memory.

Figure 19.3

Address for Stored ID Code

4 bytes

Address

NOTE:

1. The OFS register is assigned to 00FFFFh.

Refer to

Figure 19.4 OFS Register for OFS register details.

ID1

ID2

ID3

ID4

ID5

ID6

ID7

(Note 1)

Undefined instruction vector

Overflow vector

BRK instruction vector

Address match vector

Oscillation stop detection/watchdog

timer/voltage monitor 1 and voltage

monitor 2 vector

Address break

Reset vector

(Reserved)

Single step vector

00FFDFh to 00FFDCh

00FFE3h to 00FFE0h

00FFE7h to 00FFE4h

00FFEBh to 00FFE8h

00FFEFh to 00FFECh

00FFF3h to 00FFF0h

00FFF7h to 00FFF4h

00FFFBh to 00FFF8h

00FFFFh to 00FFFCh

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