adc0858civ National Semiconductor Corporation, adc0858civ Datasheet - Page 27

• Manufacturer Part Number: adc0858civ
• Description: 8-bit Analog Data Acquisition And Monitoring Systems
• Manufacturer: National Semiconductor Corporation

4 0 A D Conversion Modes
The 12-bit channel address following the mode address as-
signs the MUX configuration as per Table III(a) and (b) for
ADC0851 and ADC0858 respectively
ADC0851 only decodes the three LSBs (C0 C1 and C2) of
the channel address
The timing diagram for ‘‘Auto A D Conversion’’ mode is
shown in Figure 11 The input word is loaded starting at the
first rising edge of the CLK after CS goes low The first four
bits configure the device for the ‘‘Auto A D Conversion’’
mode while the 12-bit channel address assigns the configu-
ration of each channel pair If CS remains low after C0 is
loaded then any subsequent input data is ignored Taking
CS high after the input word is loaded initiates the start of
A D conversion A D conversion starts one to two OSC
clock periods after CS goes high The EOC output goes low
to signal the start of an A D conversion The conversion
time may range from 17 ms to 74 ms depending on how
Note that the
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the channel pairs are configured The EOC output goes high
at the end of conversion thus signalling that the result of the
A D conversion can now be retrieved The output data will
be transmitted only if CS goes low and is transmitted start-
ing at the first rising edge of CLK signal after CS goes low
The format for the output word is as follows
Data Output (DO) ADC0851 or ADC0858
TL H 11021 – 52