AMBE2000 ETC, AMBE2000 Datasheet - Page 14

• Manufacturer Part Number: AMBE2000
• Description: VOCODER CHIP
• Manufacturer: ETC

3.4
The AMBE-2000™ Vocoder Chip has an input clock frequency of 16.384 MHz. Two options are outlined below in providing
this signal. The option used is specified by the CLOCK_MODE pin 51.
The following points should be noted when designing any printed circuit board layout:
3.4.1 TTL Clock Source
If CLOCK_MODE pin is low then a TTL/CMOS source is used as the clock input. Connect X2/CLKIN and X1 as follows:
Crystal / Oscillator Usage
Reference
t
t
t
t
su
w
su
h
X2/CLKIN
(RSL)
RESETN
Figure 3-B Hardware Reset Timing Diagram
Table 3-B Reset Timing Parameters
(INT)
(RS)
CLKOUT
(RS)
CLKOUT is shown for reference only. It should not be connected in the circuit.
Hold time, RS after CLKOUT low
Pulse duration, RS low
Setup time, RS before X2/CLKIN low
Setup time, INTn, NMI, RS before CLKOUT low
Keep the crystal and external capacitors as close to the CLK_I and CLK_I2
pins as possible to minimize board stray capacitance.
Keep X2/CLKIN and X1 away from high frequency digital traces (example
CLKOUT) to avoid coupling.
Confidential Proprietary, Subject to Change
User’s Manual Version 3.0
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Parameter
t
su
(INT)
page 14
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t
su
(RS)
t
w
(RSL)
Min
t
50
10
h
0
5
(RS)
Max
Units
ns
ns
ns
s