7721 datasheet(459/577 Pages) RENESAS

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APPLICATION

7721 Group User’s Manual

16–56

16.3 Comparison of sample program execution rate

Sample program execution rates are compared in this paragraph.

The execution time ratio depends on the program or the usage conditions.

16.3.1 Differences depending on data bus width and software Wait

Internal areas are always accessed with data bus of which width is 16 bits and no software Wait. In the

external areas, the external data bus width and software Wait are selectable. Table 16.3.1 lists the sample

program (Refer to “Figure 16.3.1.”) execution time ratio depending on these selection and usable memory

areas.

Table 16.3.1 Sample program execution time ratio (external data bus width and software Wait)

Sample program execution time ratio

Sample A

1.00

1.17

1.19

1.67

1.00

1.25

1.19

1.78

0.92

Sample B

1.00

1.10

1.08

1.46

1.00

1.17

1.13

1.65

0.90

External data bus

width (unit : bit)

Memory area

ROM

External

Internal

RAM

Internal

External

Software Wait

None

Inserted

None

Inserted

None

Inserted

None

Inserted

Calculated value V

Calculated value V : The value is calculated from the shortest execution cycle number of each instruction

described in “7700 Family Software Manual.”

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