Rainbow Electronics DS1099 - Manual (Page 5)

DS1099
Low-Frequency Dual EconOscillator
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Detailed Description
The DS1099 consists of a fixed-frequency 1.048MHz
master oscillator followed by two independent factory-
programmable dividers. The two divider outputs are
connected to pins OUT0 and OUT1, which are inde-
pendently enabled/disabled using the output-enable
pins, OE0 and OE1, respectively. When the output-
enable pins are active (low), the corresponding outputs
are enabled. If either output-enable pin is tied to its
inactive state (high), then the corresponding output is
disabled and forced high immediately. The output-
enable pins only disable the corresponding output
driver(s) and do not shut down the master oscillator or
the dividers.
Since the master oscillator frequency, f MOSC , is fixed,
the frequency of OUT0 and OUT1 is determined by
DIVIDER 0 and DIVIDER 1, respectively. And since
each output has its own divider, f
OUT0
and f
OUT1
can
be programmed independent of each other.
The frequency of the outputs are calculated as follows:
f OUT0 = f MOSC / 2 X0 = 1.048MHz / 2 X0
f OUT1 = f MOSC / 2 X1 = 1.048MHz / 2 X1
where X
0
is the DIVIDER 0 setting and X
1
is the
DIVIDER 1 setting. Valid values for X 0 and X 1 are inte-
gers 0 to 22 (dec).
Table 1 shows output frequencies and divider values
for the range of divider settings.
Table 1. Divider Settings and Output
Frequencies
DIVIDER SETTING
X 0 OR X 1
DIVISOR f OUT0 OR f OUT1
0 1 1.048MHz
1 2 0.524MHz
2 4 0.262MHz
3 8 0.131MHz
4 16 65.50kHz
5 32 32.75kHz
— — —
19 524,288 2Hz
20 1,048,576 1Hz
21 2,097,152 0.5Hz
22 4,194,304 0.25Hz
Functional Diagram
DS1099
GND
MASTER
OSCILLATOR
1.048MHz
DIVIDER 0
DIVIDE BY 2 X
(X = X 0 = 0...22)
DIVIDER 1
DIVIDE BY 2 X
(X = X
1
= 0...22)
V CC
V CC
OE1
OE0
OUT0
OUT1
f OUT0
f OUT1
f MOSC
FACTORY-
PROGRAMMED
EEPROM
OUTPUT
DRIVER
OUTPUT
DRIVER