Question

in the figure below, a 68000/68230- based microcomputer is required to implement a voltmeter to measure voltage in the range 0 to 5V and display the resault in two decimal digits: one integor part and one fractional part. the microcomputer is required to start the A/D converter at the falling edge of a pulse via bit 0 of port C. when the conversion is completed, the A/D's "conversion complete" signal will go HIGH. during the conversion, the A/D's "conversion complete" signal stays LOW.

Using interrupt I/O ( Nonmaskable), repeat the task. Write the main program to configure the 68230 ports and start the A/D. The service routine will input the A/D data, display the result, and stop. write 68000 assemply language programs for the main and the service routine.

START CONVERSION PORT A BIT 6 BIT 7 CONVERSION COMPLETE --Vx o) 8-bit D1 data ANALOG VOLTAGE 0 to 5V) PORT B LO 8-bit A/D CONVERTER 7k BIT 0 PORT A TIL311 TIL311 68000/68230-based 6 Microcomputer LATCH LATCH D C BA D C BA BIT 5

Answer 1

D = 5 x (InputI255)
=Quotient +Remainder
Integer palt
This gives the integer part. The fractional part in decimal is
F = (Remainder15 1) x 10
I (Remainder)/S '
For example, suppose that the decimal equivalent of the 8-bit output of A/D is 200.
D = 20015 1 => Quotient = 3, Remainder = 47
Integer part = 3
Fractional part, F = 4715 = 9
Therefore, the display will show 3.9 V.