1 // Copyright 2023 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 15 #include "pico/critical_section.h" 16 #include "pw_chrono/system_clock.h" 17 #include "pw_unit_test/framework.h" 18 19 namespace pw::chrono::rp2040 { 20 namespace { 21 22 static_assert(pw::chrono::SystemClock::is_free_running == true); 23 TEST(ClockProperties,IsFreeRunning)24TEST(ClockProperties, IsFreeRunning) { 25 // Enter a critical section. 26 critical_section state; 27 critical_section_init(&state); 28 critical_section_enter_blocking(&state); 29 30 // Check initial clock value. 31 auto start = pw::chrono::SystemClock::now(); 32 auto end = start; 33 34 // Poll pw::chrono::SystemClock::now() until a change is detected. If no 35 // change is detected after kMaxAttempts, give up. 36 constexpr int kMaxAttempts = 100000; 37 for (int i = 0; i < kMaxAttempts; ++i) { 38 end = pw::chrono::SystemClock::now(); 39 if (end != start) { 40 break; 41 } 42 } 43 44 // Exit critical section. 45 critical_section_exit(&state); 46 47 EXPECT_GT(end, start); 48 } 49 50 } // namespace 51 } // namespace pw::chrono::rp2040 52