dsp56800eerm Freescale Semiconductor, Inc, dsp56800eerm Datasheet - Page 141

• Manufacturer Part Number: dsp56800eerm
• Description: 16-bit Digital Signal Controllers
• Manufacturer: Freescale Semiconductor, Inc

10.7 Crystal Oscillator Timing
10.8 External Memory Interface Timing
The External Memory Interface is designed to access static memory and peripheral devices.
shows sample timing and parameters that are detailed in
The timing of each parameter consists of both a fixed delay portion and a clock related portion, as well as
user controlled wait states. The equation:
When using the XTAL clock input directly as the chip clock without prescaling (ZSRC selects prescaler
clock and prescaler set to
clock input. In this situation only, parameter values must be adjusted for the duty cycle at XTAL.
DCAOE and DCAEO are used to make this duty cycle adjustment where needed.
Freescale Semiconductor
Preliminary
should be used to determine the actual time of each parameter. The terms in this equation are defined as:
Crystal Start-up time
Resonator Start-up time
Crystal ESR
Crystal Peak-to-Peak Jitter
Crystal Min-Max Period Variation
Resonator Peak-to-Peak Jitter
Resonator Min-Max Period Variation
Bias Current, high-drive mode
Bias Current, low-drive mode
Quiescent Current, power-down mode
t
D
P
M
W
= Parameter delay time
= Fixed portion of the delay, due to on-chip path delays
= Period of the system clock, which determines the execution rate of the part
= Fixed portion of a clock period inherent in the design; this number is adjusted to account
= Sum of the applicable wait state controls. The “Wait State Controls” column of
t = D + P * (M + W)
(i.e., when the device is operating at 60MHz, P = 16.67 ns)
for possible derating of clock duty cycle
Table 10-16
56F8300 Peripheral User Manual details what each wait state field controls.
Characteristic
÷ 1),
Table 10-15 Crystal Oscillator Parameters
shows the applicable controls for each parameter and the EMI chapter of the
the EMI quadrature clock is generated using both edges of the EXTAL
56F8357 Technical Data, Rev. 15
Symbol
I
I
R
BIASH
BIASL
T
T
T
T
T
I
T
ESR
PD
CS
RS
PV
RP
RJ
D
Table
0.12
Min
0.1
70
—
—
—
—
—
—
4
10-16.
0.18
Typ
250
80
—
—
—
—
—
5
0
Max
120
250
300
300
290
110
1.5
10
1
1
Crystal Oscillator Timing
ohms
Unit
Figure 10-4
ms
ms
μA
μA
μA
ps
ns
ps
ps
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