Fix nrf monotonics (#852)

* Fix nrf::timer

* Bootstrap nrf52840-blinky example

* More work on nrf blinky example

* Fix README

* Add asserts for correct timer functionality

* Add correctness check to other monotonics as well

* Update Changelog

* Fix potential timing issues

* Fix race condition in nrf::rtc

* Add changelog

* Add rtc blinky example

* Change rtc example to RC lf clock source

* Add changelog to rtic-time

* Add changelog

* Attempt to fix CI

* Update teensy4-blinky Cargo.lock

examples/nrf52840_blinky/Cargo.toml

@@ -0,0 +1,68 @@
+[package]
+authors = ["Finomnis <finomnis@gmail.com>"]
+name = "nrf52840-blinky"
+edition = "2021"
+version = "0.1.0"
+
+[workspace]
+
+[lib]
+harness = false
+
+[dependencies]
+cortex-m = { version = "0.7", features = ["critical-section-single-core"] }
+cortex-m-rt = "0.7"
+defmt = "0.3"
+defmt-rtt = "0.4"
+panic-probe = { version = "0.3", features = ["print-defmt"] }
+cortex-m-semihosting = "0.5.0"
+nrf52840-hal = "0.16.0"
+fugit = { version = "0.3.7", features = ["defmt"] }
+
+[dependencies.rtic]
+path = "../../rtic"
+version = "2.0.1"
+features = ["thumbv7-backend"]
+
+[dependencies.rtic-monotonics]
+path = "../../rtic-monotonics"
+version = "1.4.0"
+features = ["nrf52840"]
+
+# cargo build/run
+[profile.dev]
+codegen-units = 1
+debug = 2
+debug-assertions = true # <-
+incremental = false
+opt-level = 'z'         # <-
+overflow-checks = true  # <-
+
+# cargo test
+[profile.test]
+codegen-units = 1
+debug = 2
+debug-assertions = true # <-
+incremental = false
+opt-level = 3           # <-
+overflow-checks = true  # <-
+
+# cargo build/run --release
+[profile.release]
+codegen-units = 1
+debug = 2
+debug-assertions = false # <-
+incremental = false
+lto = 'fat'
+opt-level = 3            # <-
+overflow-checks = false  # <-
+
+# cargo test --release
+[profile.bench]
+codegen-units = 1
+debug = 2
+debug-assertions = false # <-
+incremental = false
+lto = 'fat'
+opt-level = 3            # <-
+overflow-checks = false  # <-