""" mbed SDK Copyright (c) 2011-2013 ARM Limited Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. """ from time import time class WaitusTest(): """ This test is reading single characters from stdio and measures time between their occurrences. """ TICK_LOOP_COUNTER = 13 TICK_LOOP_SUCCESSFUL_COUNTS = 10 DEVIATION = 0.10 # +/-10% def test(self, selftest): test_result = True # First character to start test (to know after reset when test starts) if selftest.mbed.set_serial_timeout(None) is None: return selftest.RESULT_IO_SERIAL c = selftest.mbed.serial_read(1) if c is None: return selftest.RESULT_IO_SERIAL if c == '$': # target will printout TargetID e.g.: $$$$1040e649d5c09a09a3f6bc568adef61375c6 #Read additional 39 bytes of TargetID if selftest.mbed.serial_read(39) is None: return selftest.RESULT_IO_SERIAL c = selftest.mbed.serial_read(1) # Re-read first 'tick' if c is None: return selftest.RESULT_IO_SERIAL start_serial_pool = time() start = time() success_counter = 0 for i in range(0, self.TICK_LOOP_COUNTER): c = selftest.mbed.serial_read(1) if c is None: return selftest.RESULT_IO_SERIAL delta = time() - start deviation = abs(delta - 1) # Round values delta = round(delta, 2) deviation = round(deviation, 2) # Check if time measurements are in given range deviation_ok = True if delta > 0 and deviation <= self.DEVIATION else False success_counter = success_counter+1 if deviation_ok else 0 msg = "OK" if deviation_ok else "FAIL" selftest.notify("%s in %.2f sec (%.2f) [%s]"% (c, delta, deviation, msg)) start = time() if success_counter >= self.TICK_LOOP_SUCCESSFUL_COUNTS: break measurement_time = time() - start_serial_pool selftest.notify("Consecutive OK timer reads: %d"% success_counter) selftest.notify("Completed in %.2f sec" % (measurement_time)) test_result = True if success_counter >= self.TICK_LOOP_SUCCESSFUL_COUNTS else False return selftest.RESULT_SUCCESS if test_result else selftest.RESULT_FAILURE