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Hardware Testing Learnings

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  1. Hardware Testing Learnings These are things I learned the hard way as I tested the circuit and need to remember if I go back in to do more testing… • Must use “DontPowerDownOnSleep” or robot will shut down when testing sleep • “SimulateHang” debug setting must be used in order to test timings or the watchdog snooze will come on and mess up timings • “SimulateHang” must be turned off to test watchdog mode because it causes the service to ignore manually setting the timer into this mode • For 10V the logic threshold should really be 7V, but our reader can only do 6 • The true GPIO input is 0-5V so it won’t register properly • The prob acts as a 200K resistor and thus can have strong probe effect on anything but the output of a logic gate. Only use on the output of logic gates

  2. Startup • Sample Rate = 200KHz • Confirmed test values • PowerOnReset signal stays on for 168mSec (should be nominally 200 mSec) • Why does BeginChargingOutput take 264 mSec to go high? • Because it has 320K of resistance in its RC circuit due to Collector resistor on Q2. 300K would produce this timing, but within tolerance • After BeginChargingOutput goes high, RestartTimer pulses for 170mSec (should be nominally 200 mSec) • BegingChargingOutput also spuriously pulses on startup because flip flop initially starts out as high • Why does Watchdog Mode take 8.5mSec to go high? • Unclear, but it doesn’t seem to matter d) 8.5 mSec (c) 122.5ms (a) 15.5 msec a)168.0 mSec c) 170.0 mSec b) 264 mSec

  3. Watchdog Reset • Sample Rate = 5MHz, temporarily changed watchdog to reset after 86 seconds to make testing easier • Confirmed test values • a) Watchdog On & OK Signal goes off for 17.5 sec (nominally 18.4 seconds, close enough) • b) Why does Watchdog On & OK Signal take 17.5 sec to turn on? • Because D Flip Flop U10 initially starts with Q on, and it takes 17.5 seconds to turn off • c) Is it OK that charge finished signal only stays on for 200nSec? • Only consumed by Watchdog Reset Circuit, and only as a clock input. 4013B has a min clock width of 55 nSec so this should be OK. • d) Robot stays on for 83 sec before resetting (nominally should be 86 seconds, close enough) (a) 17.5 Sec (b) 17.5 Sec (c)200nSec (a) 15.5 msec 170.0 mSec b) 264 mSec (d)83 sec

  4. Watchdog Snooze • Sample Rate = 100MHz, temporarily changed watchdog to reset after 86 seconds (1.43 min) to make testing easier • Confirmed test values • A) When the watchdog is snoozed, does the timer restart? Yes, 1.37 min after a snooze • B) If left to finish a cycle, does it wait the full time before resetting? Yes, 1.39 min manual snooze (b) 17.5 Sec (c)200nSec (a) 15.5 msec 170.0 mSec a) 1.37 min a) 1.39 min

  5. Sleep • Sample Rate = 100MHz, temporarily changed Temp Sleep to reset after 5.7 min to make testing easier • Confirmed test values • A) Does it take three minutes to come out of watchdog mode? It takes 2.65 min. Close enough. • B) Does the power shut off when out of watchdog mode? Yes. • C) Does the power come back on when the Temp Sleep is over? • D) Does it take 5.7 min to turn back on? Yes, It takes 5.65 min from Restart Timer to charge finished. • Notes • E) Spurious high signals appear on BeginChargingOutput sometimes. This causes RestartTimer to fire more than once. Theory: Due to the capacitor driving the input directly and not using a Schmitt trigger. Not an issue because it just means we start the timing a little late. (a) 17.5 Sec (b) 17.5 Sec b) Power off e) Spurious high signals c) Power on (a) 15.5 msec 170.0 mSec a) 2.65 min d) 5.65 min (d)83 sec

  6. Oddities

  7. Oscillations • Sample Rate = 500MHz • Not(WatchdogMode) oscillates because the input into the AND gate that feeds it is coming from an RC circuit directly and not going through a Schmitt trigger. Changed circuit to use a schmitt trigger and this fixed it