Week 10 Tuesday -- MAE 412
Lecture:
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Optical Proximity Detector Circuit -- potential problem
-- missed events from too low a sampling frequency -- don't forget that
the ISR suspends the USER program for 8.3 msec every 41.5 msec.
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Solution -- /R/S Flip-Flop -- truth table
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Aside: SPDT Switch Debouncer using /R/S Flip-Flop
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Hall Effect Sensor -- Schmitt-trigger input / open collector
output
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Point-to-Point Trolley Control using Diodes
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Polarity reversal using DPDT relay or switch
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Mechanical Sensors / Limit Switches
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Rule 17 - "... All devices should be disabled when I/O
port lines are high (true)." Why?
Assignments and Reference Material:
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For information about the Interrupt Service Routine read
Chapter 5 on Communications by Gurion and Simon in Volume 1 of the On-line
Text.
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For information about the Bar-Code Reader, RR Signal Control,
and Interlocking Control (Track Kill) read Chapter 6 on Block Management
by Lecky and Fiderer in Volume 1 of On-line Text.
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Read Chapter 2 of Volume 1 of the On-line Text ("Hornby
Railways ...")
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Document your working computer using ORCAD (see example
on CIRCUITS page) -- Hand in next Tuesday (include 74LS244 buffer).
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Read Chapter 3 of CST -- available on-line (go to BLACKBOARD
=> LIBRARY => e-reserves => authentication page => user:mae412 password:littman1).
Continue studying the 6502 instruction set.