Diff: README.md

Revision:

16:ed2c228cbc9c

Parent:

14:83b73695da8f

Child:

20:759aab916d47

--- a/README.md	Fri Feb 21 11:16:49 2020 +0800
+++ b/README.md	Fri Feb 21 11:19:30 2020 +0800
@@ -6,10 +6,11 @@
 automatically when CPU is idle.
 
 ## Supported platforms
+
+- [NuMaker-PFM-NANO130](https://os.mbed.com/platforms/NuMaker-PFM-NANO130/)
 - [NuMaker-PFM-NUC472](https://os.mbed.com/platforms/Nuvoton-NUC472/)
 - [NuMaker-PFM-M453](https://os.mbed.com/platforms/Nuvoton-M453/)
 - [NuMaker-PFM-M487](https://os.mbed.com/platforms/NuMaker-PFM-M487/)
-- [NuMaker-PFM-NANO130](https://os.mbed.com/platforms/NuMaker-PFM-NANO130/)
 
 ## Supported wake-up source
 - Button(s)
@@ -21,43 +22,32 @@
 
 ## Choose idle handler
 Application user can choose to use Mbed OS internal idle handler or customize its own one.
-1. To use Mbed OS internal idle handler, ensure the `MBED_TICKLESS` macro is defined in `mbed_app.json`.
-1. To customize idle handler, ensure the `MBED_TICKLESS` macro is not defined in `mbed_app.json`.
-   This gives flexibility for providing platform-dependent idle handler.
-   The `idle_hdlr` in `main.cpp` is a trivial example.
+1.  To use Mbed OS internal idle handler, ensure the `MBED_TICKLESS` macro is defined and `tickless-from-us-ticker` is configured to false in `mbed_app.json`.
 
-<pre>
-{
+    ```json
     "target_overrides": {
+        ......
         "NUMAKER_PFM_NUC472": {
-            "target.macros_add": ["OS_IDLE_THREAD_STACK_SIZE=512", <b>"MBED_TICKLESS"</b>],
-            "target.gpio-irq-debounce-enable-list": "SW1, SW2",
-            "target.gpio-irq-debounce-clock-source": "GPIO_DBCTL_DBCLKSRC_IRC10K",
-            "target.gpio-irq-debounce-sample-rate": "GPIO_DBCTL_DBCLKSEL_256"
-        },
-</pre>
+            "target.macros_add": ["MBED_TICKLESS"],
+            "target.tickless-from-us-ticker": false,
+        ......
+    ```
+
+    **Note**: To enable tickless on existent project, just define `MBED_TICKLESS` and configure `tickless-from-us-ticker` to false as above.
+
+1.  To customize idle handler, ensure the `MBED_TICKLESS` macro is not defined in `mbed_app.json`.
+    This gives flexibility for providing platform-dependent idle handler.
+    The `idle_hdlr` in `main.cpp` is a trivial example.
 
 ## Execution
 To run this tickless example, target board must run with no ICE connected.
 With ICE connected, system will enter **Idle** mode (shallow sleep) rather than **Power-down** mode (deep sleep)
-even though `deepsleep()` is called.
-
-### Modes
-There are two modes on Nuvoton Mbed-enabled boards:
-
-#### MASS mode
-This mode supports drap-n-drop programming and VCOM. For retrieving chip information, ICE is connected and system cannot enter
-**Power-down** mode.
+even though `CLK_PowerDown()` is called.
 
-#### Debug mode
-This mode supports debugger and VCOM. But without entering debug session for debugging, ICE isn't connected and system can enter
-**Power-down** mode (deep sleep).
+**Note:** With old Nu-Link1 firmware version, ICE is unexpected connected in MASS mode. Update to the latest Nu-Link firmware version to fix the issue.
 
-So to run this tickless example, user must switch to **MASS** mode first for drag-n-drop programming and 
-then switch to **Debug** mode without entering debug session for running the code.
-
-### Note for terminal output
-With your terminal program configured with 9600/8-N-1, you would see output with:
+### Terminal output
+With your terminal program configured with 115200/8-N-1, you would see output with:
 <pre>
 I am going to shallow/deep sleep
 Wake up by WDT timeout from <b>deep sleep</b>
@@ -80,18 +70,7 @@
 1. If you see `Unidentified`, it means chip is waken up from **Power-down** mode but its wake-up source is unidentified.
 Usually it is `lp_ticker` which is internal with the tickless mechanism.
 
-## Known issues
-1. Since mbed OS **5.6.2**, `Ticker`, `Timeout`, and `Timer` could work correctly with this example.
-But use of them would lock deep sleep and cause the system from entering into deep sleep mode.
-It is because these timers rely on internal `us_ticker`, which relies on high-res clocks HXT/HIRC,
-which are forced to stop in deep sleep mode to save more power.
-To ensure these timers work correctly, the system is guarded from entering into deep sleep mode during their use.
+## Reference
 
-1. Use of interrupt callback and asynchronous transfer in `Serial`, `SPI`, `CAN`, etc. has the same issue as above.
-
-1. Use of wait series functions (`wait`/`wait_ms`/`wait_us`) has the same issue as above.
-During the wait time, the system is guarded from entering deep sleep mode.
-
-1. Use of `EventQueue` has the same issue as above because `EventQueue` relies on `Timer`/`Ticker` for its internal counting.
-
-1. Use of `RtosTimer` can work seamlessly with this example because `RtosTimer` relies on system timer rather than `us_ticker`.
+-   [Tickless kernel](https://en.wikipedia.org/wiki/Tickless_kernel)
+-   [Mbed tickless](https://os.mbed.com/docs/mbed-os/v5.15/porting/tickless.html)