Design a "missing pulse detector" similar to the one designed in Problem 14-13. It will be used to monitor the DAV input line in the 4096/4196 schematic. Assume that the DAV line is supposed to provide a 2-μs HIGH pulse every 100 μs Monitor the DAV line with a 74123 monostable multivibrator. Have the 74123 output a HIGH to port 1, bit 7 (P1.7) of the 8031 microcontroller if a missing pulse is detected.
Problem 14-13
The NPRO microprocessor control line is supposed to issue a 10-μs LOW pulse every 150 μs as long as a certain process is running smoothly. Design a "missing pulse detector" using a 74123 that will normally output a HIGH but will output a LOW if a single pulse on the NPRO line is skipped. (Hint: The 74123 will be retriggered by NPRO every 150 μs.)