Update documentation for RTT (#85)

Resolves #73

Author: VladimirUmek

documentation/doxygen/src/images/blocks.pptx

@@ -34,13 +34,14 @@ The subcomponent selection allows you to change the target hardware interface of
 
 The following subcomponents are available:
 
- Variant              | Description
-:---------------------|:-------------------
-**Breakpoint**        | When the I/O stream is used, the application stops with [BKPT](https://developer.arm.com/documentation/100073/latest/The-Arm-C-and-C---Libraries/Support-for-building-an-application-with-the-C-library/Using-the-C-and-C---libraries-with-an-application-in-a-semihosting-environment?lang=en) instruction. No additional code is required.
-**Event Recorder**    | STDOUT and STDERR can be redirected using the [Event Recorder](https://arm-software.github.io/CMSIS-View/main/evr.html) (especially interesting for targets without ITM (such as Cortex-M0/M0+/M23)).
-**ITM**               | Use [Instrumentation Trace Macrocell (ITM)](https://developer.arm.com/documentation/ddi0314/h/Instrumentation-Trace-Macrocell?lang=en) for I/O communication via the debugger (only available for Cortex-M3/M4/M7/M33/M55/M85 processors).<br/> Usually, data is shown in a dedicated window.<br/> No additional code is required to output or input data through the ITM channel. However, you have to configure the ITM channel for tracing.
-**UART**              | Retarget I/O streams to UART. Default implementation variant uses CMSIS-Driver USART.
-**Custom**            | Retarget I/O stream to a user defined interface (such as custom UART implementation or other application specific interface).<br/>See \subpage custom_subcomponent for further details.
+ Variant           | Description
+:------------------|:-------------------
+**Breakpoint**     | When the I/O stream is used, the application stops with [BKPT](https://developer.arm.com/documentation/100073/latest/The-Arm-C-and-C---Libraries/Support-for-building-an-application-with-the-C-library/Using-the-C-and-C---libraries-with-an-application-in-a-semihosting-environment?lang=en) instruction. No additional code is required.
+**Event Recorder** | STDOUT and STDERR can be redirected using the [Event Recorder](https://arm-software.github.io/CMSIS-View/main/evr.html) (especially interesting for targets without ITM (such as Cortex-M0/M0+/M23)).
+**ITM**            | Use [Instrumentation Trace Macrocell (ITM)](https://developer.arm.com/documentation/ddi0314/h/Instrumentation-Trace-Macrocell?lang=en) for I/O communication via the debugger (only available for Cortex-M3/M4/M7/M33/M55/M85 processors).<br/> Usually, data is shown in a dedicated window.<br/> No additional code is required to output or input data through the ITM channel. However, you have to configure the ITM channel for tracing.
+**RTT**            | Retarget I/O streams to SEGGER RTT Channel 0.
+**UART**           | Retarget I/O streams to UART. Default implementation variant uses CMSIS-Driver USART.
+**Custom**         | Retarget I/O stream to a user defined interface (such as custom UART implementation or other application specific interface).<br/>See \subpage custom_subcomponent for further details.
 
 
 > **Note**

documentation/doxygen/src/images/component-selection.png

@@ -19,17 +19,116 @@ cpackget add ARM::CMSIS-Compiler
 Alternatively, you can download the latest version from the
 [CMSIS-Compiler](https://www.keil.arm.com/packs/cmsis-compiler-arm/versions/) page.
 
-## Component selection and usage
+## Component selection
 
 1. In your IDE, open the
    [Manage software components](https://mdk-packs.github.io/vscode-cmsis-solution-docs/create_app.html#software-components)
    dialog.
 2. If you cannot see the **CMSIS-Compiler** component, select to display **All installed packs**.
 3. You must select the component **CMSIS-Compiler::CORE** and at least one additional **API**.
 
+
 ![Manage software components](./images/component-selection.png)
 
+## Resolve Dependencies {#usage_resolve_dependencies}
+
+### Using Event Recorder {#usage_evr}
+
+The **Event Recorder** subcomponent requires the `CMSIS-View::Event Recorder` component from the [CMSIS-View](https://www.keil.arm.com/packs/cmsis-view-arm/) pack.
+
+1) Install the **CMSIS-View** pack:
+
+   ```sh
+   cpackget add ARM::CMSIS-View
+   ```
+
+2) In the **Manage Software Components** dialog, select **Software Pack**, then choose **All installed packs** and find and select **ARM::CMSIS-View**.
+
+   ![Select CMSIS-View Pack](./images/stdio_evr_pack.png)
+
+3) Select the **CMSIS-View::Event Recorder** component.
+
+   ![Select CMSIS-View::Event Recorder Component](./images/stdio_evr_components.png)
+
+The project yml file should contain:
+
+```yml
+packs:
+   - pack: ARM::CMSIS-Compiler
+   - pack: ARM::CMSIS-View
+```
+
+```yml
+components:
+   - component: CMSIS-Compiler:CORE
+   - component: CMSIS-Compiler:STDOUT:Event Recorder
+   - component: CMSIS-View:Event Recorder&DAP
+```
+
+### Using RTT {#usage_rtt}
+
+The **RTT** subcomponent requires the `SEGGER::RTT` component from the [SEGGER RTT](https://www.keil.arm.com/packs/rtt-segger/) pack.
+
+1) Install the **SEGGER RTT** pack:
+
+   ```sh
+   cpackget add SEGGER::RTT
+   ```
+
+2) In the **Manage Software Components** dialog, select **Software Pack**, then choose **All installed packs** and find and select **SEGGER::RTT**.
+
+   ![Select SEGGER Pack](./images/stdio_rtt_pack.png)
+
+3) Select the **SEGGER::RTT** component.
+
+   ![Select SEGGER::RTT Component](./images/stdio_rtt_components.png)
+
+The project yml file should contain:
+
+```yml
+packs:
+   - pack: ARM::CMSIS-Compiler
+   - pack: SEGGER::RTT
+```
+
+```yml
+components:
+   - component: CMSIS-Compiler:CORE
+   - component: CMSIS-Compiler:STDOUT:RTT
+   - component: SEGGER:RTT
+```
+
+### Using UART {#usage_uart}
+
+The **UART** subcomponent provides default implementation variant **CMSIS** which requires the `CMSIS Driver::USART` implementation, typically provided by a Board Support Pack (BSP) or Device Family Pack (DFP) for the target hardware.
+
 > **Note**
 >
-> Refer to the sections [Low-level I/O](./rt_io.md) and
-> [Multithreading Support Retarget](./rt_os.md) for more information about the retargeting options.
+> Use the [CMSIS Packs catalog](https://www.keil.arm.com/packs/) to find the appropriate pack for your target hardware.
+
+1) Install the Board Support Pack (BSP) or Device Family Pack (DFP):
+
+   ```sh
+   cpackget add Vendor::Pack
+   ```
+
+2) In the **Manage Software Components** dialog, select **Software Pack**, then choose **All installed packs** and find and select installed BSP or DFP.
+
+3) Select the **CMSIS Driver::USART** component.
+
+   ![Select CMSIS Driver::USART Component](./images/stdio_uart_components.png)
+
+The project yml file should contain:
+
+```yml
+packs:
+   - pack: ARM::CMSIS-Compiler
+   - pack: Vendor::Pack
+```
+
+```yml
+components:
+   - component: CMSIS-Compiler:CORE
+   - component: CMSIS-Compiler:STDOUT:UART&CMSIS
+   - component: CMSIS Driver:USART
+```