7733 datasheet(630/940 Pages) RENESAS

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APPENDIX

7733 Group User’s Manual

21-82

Appendix 9. Q & A

Questions about the memory allocation selection function are described below:

For what purpose is this function used?

Is there any precaution on use of this function?

Memory

This function is used in order to secure an external memory area to bank 0 16 in the memory

expansion mode.

If there is an external device which is frequently accessed, this device’s memory allocation in bank

016 is effective for accessing this device, as well as internal RAM and SFR, with using DPR and

DT efficiently. In the M37733MHBXXXFP, all of bank 016 is specified as an area for internal

resources. Therefore, this function is used to secure an external memory area in bank 016.

Note that the memory allocation selection bits are valid in the single-chip mode, also. In the single-

chip mode, the memory allocation selection function is valid only for reduction of usable ROM area.

Therefore, in the single-chip mode, we recommend to set these bits to “0002” (the state immedi-

ately after reset) and not to change them.

Note the following:

• When changing the memory allocation selection bits, follow the procedure in Figure 2.4.1.

• When changing the memory allocation selection bits, make sure that the change is done within

an area which is in the internal ROM area both of after and before the change, for example

addresses 00C00016 to 00FFFF16.

• We recommend to set the memory allocation selection bits only when a processor mode is set

after reset and not to change them after this setting.

• When programming to the EPROM and one time PROM versions, program to addresses listed in

Table 19.1.3.

• As for debugging for an area in bank 016 or 116 which is specified as an external area, some

considerations may be necessary. For details concerning the development support tools, refer to

the respective operation manuals.

7733 Datasheet(PDF) 630 Page - Renesas Technology Corp