ADC12034 National Semiconductor Corporation, ADC12034 Datasheet - Page 39

• Manufacturer Part Number: ADC12034
• Description: Self-calibrating 12-bit Plus Sign Serial I/o A/d Converters With Mux And Sample/hold
• Manufacturer: National Semiconductor Corporation

A sample program, written in Microsoft QuickBasic, is shown
on the next page. The program prompts for data mode select
instruction to be sent to the A/D. This can be found from the
Mode Programming table shown earlier. The data should be
entered in “1”s and “0”s as shown in the table with DI0 first.
Next the program prompts for the number of SCLKs required
for the programmed mode select instruction. For instance, to
send all “0”s to the A/D, selects CH0 as the +input, CH1 as
the −input, 12-bit conversion, and 13-bit MSB first data output
format (if the sign bit was not turned off by a previous instruc-
tion). This would require 13 SCLK periods since the output
data format is 13 bits.
The ADC powers up with No Auto Cal, No Auto Zero, 10
CCLK Acquisition Time, 12-bit conversion, data out with sign,
39
power up, 12- or 13-bit MSB first, and user mode. Auto Cal,
Auto Zero, Power Up and Power Down instructions do not
change these default settings. The following power up se-
quence should be followed:
1.
2.
3.
It is recommended that the first instruction issued to the
ADC12038 be Auto Cal (see Section 1.1).
Run the program
Prior to responding to the prompt apply the power to the
ADC12038
Respond to the program prompts
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