dsp56852 Freescale Semiconductor, Inc, dsp56852 Datasheet - Page 22

• Manufacturer Part Number: dsp56852
• Description: 56800e 16-bit Digital Signal Controllers Digital Signal Controller
• Manufacturer: Freescale Semiconductor, Inc

4.5.2
The recommended method of connecting an external clock is given in
source is connected to XTAL and the EXTAL pin is held at ground (recommended), V
The TOD_SEL bit in CGM must be set to 1.
4.5.3
The recommended method of connecting an external clock is given in
source is connected to XTAL and the EXTAL pin is held at V
set to 0 or 1. 0 is recommended.
22
Operating Conditions: V
Frequency of operation (external clock driver)
Clock Pulse Width
External clock input rise time
External clock input fall time
1. See
2. External clock input rise time is measured from 10 to 90 percent.
3. External clock input fall time is measured from 90 to 10percent.
4. Parameters listed are guaranteed by design.
Figure 4-7 Connecting a High Speed External Clock Signal using XTAL
Figure 4-8 Connecting a Low Speed External Clock Signal using XTAL
High Speed External Clock Source (> 4MHz)
Low Speed External Clock Source (2-4MHz)
Figure 4-7
Table 4-5 External Clock Operation Timing Requirements
Characteristic
SS
4
for details on using the recommended connection of an external clock driver.
= V
SSIO
= V
3, 4
2, 4
SSA
= 0V, V
DD
(up to 240MHz)
56852 Technical Data, Rev. 8
= 1.62-1.98V, V
External
1
(2-4MHz)
XTAL
Clock
External
XTAL
Clock
56852
Symbol
56852
f
t
t
DDIO
t
osc
PW
rise
fall
EXTAL
GND,
EXTAL
or V
= V
V
DDA
DDA
V
DDA
DDA
= 3.0–3.6V, T
/2
6.25
Min
DDA
—
—
/2
0
,
/2. The TOD_SEL bit in CGM may be
A
= –40° to +120°C, C
Typ
Figure
Figure
—
—
—
—
4-7. The external clock
4-8. The external clock
Freescale Semiconductor
Max
TBD
TBD
240
L
—
4
£ 50pF, f
DDA
, or V
op
= 120MHz
Unit
MHz
ns
ns
ns
DDA
/2.