127
CPU System Functions
Chapter 3
Preliminary User’s Manual U17566EE1V2UM00
Data access
The given numbers of cycles in
Table 3-17
describe the time additionally
required when an instruction accesses data in the respective memory.
Note that data accesses are always random accesses.
Table 3-16
Single-cycle instructions execution times in CPU clock cycles
Memory
Access type
µ
PD70F3427
µ
PD70F3424
µ
PD70F3425
µ
PD70F3426
µ
PD70F3421
µ
PD70F3422
µ
PD70F3423
µ
PD703420
µ
PD703421
µ
PD703422
VFB flash
Consecutive
1
1
1
1
–
Random
3
a
a)
These values include the additional clock cycle, cause by the CPU’s pipeline break
3
a
3
a
1
a
–
VFB ROM
Consecutive
–
–
–
–
1
Random
–
–
–
–
1
a
VDB RAM
Consecutive
1
1
1
1
1
Random
1
a
1
a
1
a
1
a
1
a
VSB flash
Consecutive
–
–
2
–
–
Random
–
–
5
a
–
–
VSB RAM
Consecutive
–
–
2
–
–
Random
–
–
3
a
–
–
Table 3-17
Additional time for data accesses in CPU clock cycles
Data access
memory
Instruction
code fetch bus
µ
PD70F3427
µ
PD70F3424
µ
PD70F3425
µ
PD70F3426
µ
PD70F3421
µ
PD70F3422
µ
PD70F3423
µ
PD703420
µ
PD703421
µ
PD703422
VFB flash
VFB
4
4
4
1
–
VFB ROM
VFB
–
–
–
–
1
VDB RAM
VFB/VSB
0
0
0
0
0
VSB flash
VFB
–
–
4
–
–
VSB RAM
VFB
–
–
•
1 (single
access)
•
3 (multiple
access)
–
–
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