C517A_99 Datasheet, PDF (46/218 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

External Bus Interface
C517A
a)
One Machine Cycle
One Machine Cycle
S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6
ALE
PSEN
RD
P2
(A)
without
MOVX
PCH
PCH
PCH
PCH
OUT
OUT
OUT
OUT
P0
INST. PCL
IN OUT
INST. PCL
IN OUT
INST. PCL
IN OUT
INST. PCL
IN OUT
INST.
IN
PCL OUT
valid
PCL OUT
valid
PCL OUT
valid
PCL OUT
valid
b)
One Machine Cycle
One Machine Cycle
S1 S2 S3 S4 S5 S6 S1 S2 S3 S4 S5 S6
ALE
PSEN
RD
P2
PCH
DPH OUT OR
OUT
P2 OUT
P0
INST. PCL
IN OUT
INST.
IN
DATA
IN
PCL OUT
valid
DPL or Ri
valid
(B)
with
MOVX
PCH
OUT
PCL
OUT
PCL OUT
valid
INST.
IN
MCT03220
Figure 4-1
External Program Memory Execution
Semiconductor Group
4-2