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- """
- 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
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