AN2408 Freescale Semiconductor / Motorola, AN2408 Datasheet - Page 13

• Manufacturer Part Number: AN2408
• Description: Examples of HCS12 External Bus Design A Companion Note to AN2287/D
• Manufacturer: Freescale Semiconductor / Motorola

Freescale Semiconductor
LATCHED_ADDR
ADDR/DATA
RAM_DATA
RAM_R/W
ECS/XCS
SYSCLK
ECLK
ECLK
R/W
0 ns
S0
t
CSD
25 ns
EXTERNAL READ CYCLE
t
t
AD
RWD
ADDR
t
S1
P
:373
Examples of HCS12 External Bus Design, Rev. 2
Figure 12. Example Timing Analysis
S2
t
MAH
t
t
t
t
Z
ELQV
GLQV
AVQV
RAM DATA
RAM DATA
Example #4 — Byte-Wide SRAM Interface (Narrow Mode) XCS/ECS Gated
t
DSR
50 ns
S3
S0
t
t
t
CSH
RWH
P
t
t
Z
GHQZ
:373
t
EXTERNAL WRITE CYCLE
CSD
t
AD
ADDR
t
S1
P
:373
75 ns
S2
t
MAH
t
P
t
MCU DATA
t
DDW
Z
MCU DATA
S3
100 ns
t
t
t
t
S0
P
CSH
DHW
Z
t
t
CSD
P
:373
EXTERNAL WRITE CYCLE
t
AD
ADDR
t
S1
P
:373
S2
t
t
MAH
P
125 ns
t
t
MCU DATA
DDW
Z
MCU DATA
S3
INTERNAL CYCLE
S0
t
t
t
t
CSH
DHW
RWH
Z
t
P
t
t
RWD
P
:373
150 ns
S1
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