Datasheet

ADC0801, ADC0802
ADC0803, ADC0804, ADC0805
SNOSBI1B –NOVEMBER 2009–REVISED FEBRUARY 2013 www.ti.com
SAMPLE PROGRAM FOR Figure 61 INTERFACING MULTIPLE A/D’s IN AN MC6800 SYSTEM
SAMPLE PROGRAM FOR Figure 61 INTERFACING MULTIPLE A/D’s IN AN MC6800 SYSTEM
Note: In order for the microprocessor to service subroutines and interrupts, the stack pointer must be
dimensioned in the user’s program.
For amplification of DC input signals, a major system error is the input offset voltage of the amplifiers used for
the preamp. Figure 62 is a gain of 100 differential preamp whose offset voltage errors will be cancelled by a
zeroing subroutine which is performed by the INS8080A microprocessor system. The total allowable input offset
voltage error for this preamp is only 50 µV for /⁄4 LSB error. This would obviously require very precise amplifiers.
The expression for the differential output voltage of the preamp is:
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