ST STM32F40 Series User Manual

RM0090 Embedded Flash memory interface
Doc ID 018909 Rev 4 64/1422
Figure 4. Sequential 32-bit instruction execution
When the code is not sequential (branch), the instruction may not be present in the currently
used instruction line or in the prefetched instruction line. In this case (miss), the penalty in
terms of number of cycles is at least equal to the number of wait states.
@
@
@
@
F
F
F
F
D
D
D
D
E
E
E
E
@
@
@
@
F
F
F
F
D
D
D
E
E
1111
2222
3333
444 4
5555
6666
777
88
Read ins 1, 2, 3, 4 Gives ins 1, 2, 3, 4 Read ins 5, 6, 7, 8 Gives ins 5, 6, 7, 8
ins 1
fetch
ins 2
fetch
ins 3
fetch
ins 4
fetch
ins 5
fetch
ins 6
fetch
ins 7
fetch
ins 8
fetch
WAIT
WAIT
DE
44
@
@
F
F
F
F
D
D
D
E
E
5
55
66 6
777
88
@
@
@
@
@
F
F
F
F
D
D
D
E
E
Wait data
@
1111
2222
333
44
5
E
3
Read ins 1, 2, 3, 4 Gives ins 1, 2, 3, 4 Gives ins 5, 6, 7, 8
Read ins 5, 6, 7, 8 Read ins 9, 10, ...
ins 4 ins 5
fetch
ins 6 ins 7
Without prefetch
With prefetch
FDE
@
Cortex-M4 pipeline
AHB protocol
@ : address requested
F: Fetch stage
D: Decode stage
E: Execute stage
ins 1
fetch
ins 2
fetch
ins 3
fetch fetch fetch fetch
ins 8
fetch
MS31831V1

ST STM32F40 Series Specifications

General

Brand	ST
Model	STM32F40 Series
Category	Microcontrollers
Language	English