MC56F8346 Freescale Semiconductor, Inc, MC56F8346 Datasheet - Page 148

• Manufacturer Part Number: MC56F8346
• Description: 56f8300 16-bit Digital Signal Controllers
• Manufacturer: Freescale Semiconductor, Inc

and DCAEO are used to make this duty cycle adjustment where needed.
DCAOE and DCAEO are calculated as follows:
The timing of write cycles is different when WWS = 0 than when WWS > 0. Therefore, some parameters
contain two sets of numbers to account for this difference. Use the “Wait States Configuration” column of
Table 10-16
Note:
148
A0-Axx,CS
DCAOE =
DCAEO =
D0-D15
WR
RD
Note: During read-modify-write instructions and internal instructions, the address lines do not change state.
When multiple lines are given for the same wait state configuration, calculate each and then select the
smallest or most negative.
to make the appropriate selection.
=
=
Example of DCAOE and DCAEO calculation
Assuming prescaler is set for ÷ 1 and prescaler clock is selected by ZSRC, if XTAL duty cycle
ranges between 45% and 60% high:
DCAOE = .50 - .60 = - 0.1
DCAEO = .45 - .50 = - 0.05
0.5 - MAX XTAL duty cycle, if ZSRC selects prescaler clock and the prescaler is set to ÷ 1
0.0 all other cases
MIN XTAL duty cycle - 0.5, if ZSRC selects prescaler clock and the prescaler is set to ÷ 1
0.0 all other cases
t
Figure 10-4 External Memory Interface Timing
WRWR
t
AWR
t
DWR
t
Data Out
DOS
56F8346 Technical Data, Rev. 15
t
WR
t
DOH
t
WAC
t
WRRD
t
ARDA
t
AD
t
ARDD
t
RDD
t
RD
Data In
t
DRD
t
RDA
Freescale Semiconductor
t
RDRD
t
RDWR
Preliminary