EWL for Kinetis Development

Codewarrior GCC ARM Build Tools use EWL (Embedded Warrior Library) as a default library. EWL library set aims at reducing the memory footprint taken by IO operations and introduces a simpler memory allocator. To use newlib available with GCC instead of EWL, refer to the topic: Convert Kinetis Project to use newlib instead of EWL.

EWL Librarian I/O model is divided into 6 modes for C language:

ewl- I/O operations through UART port.
ewl_hosted- I/O operations through debugger console.
ewl_noio- no I/O support, printf or scanf .
c9x- same as ewl with additional wide char support.
c9x_hosted- same as ewl_hosted with additional wide char support.
c9x_noio- same as ewl_noio with additional wide char support.

Similarly, for C++, 6 sets of Librarian modes are supported.

ewl_c++
ewl_c++_hosted
ewl_c++_noio
c9x_c++
c9x_c++_hosted
c9x_c++_noio

The I/O modes can be selected depending on requirement while creating the project as illustrated below.

Figure 1. Language and Build Tools Options

Following library configurations are selected depending on the I/O mode:

UART (default) - Librarian Model as ‘ewl’.
Debugger Console - Librarian Model as ‘ewl_hosted’ .
No I/O- Librarian Model as ‘ewl_noio’.

Similarly when C++ language is selected, c++ versions are picked.

Note: For UART I/O mode, additional configuration is required. For details, refer Set up UART Connections.

Following image shows compiler settings showing Librarian Model and its modes.

Figure 2. Compiler Settings - Librarian Model

The printing and scanning formatters for EWL are grouped in an effort to provide only the support required for the application:

int - integer and string processing
int_FP - integer, string and floating point
int_LL - integer (including long long) and string
int_FP_LL - all but wide chars

The above options can be selected at Print Formats and Scan Formats drop down box provided under Librarian panel. This is shown below.

Figure 3. Compiler Settings - Print Formats

EWL libraries are prebuilt for several configurations. They are placed at [CW Install Dir]/MCU/ARM_GCC_Support/ewl/lib. Library is built for cortex-m0 and cortex-m4 ARM targets.

armv6-m for cortex-m0 and
armv7e-m for cortex-m4
1. armv7e-m- Software floating-point
2. armv7e-m/fpu- Hardware floating-point with hardware FP ABI
3. armv7e-m/softfp- Hardware floating-point with soft FP ABI
4. armv7e-m/spfp- Same as softfp but built with –fshort-double enabled, where double has same size as float.

Each target lib has following components:

libc.a - c library
libc99.a - c library with c99 support
libc++.a- c++ library
libstdc++.a- c++ with c99 support
libhosted.a- library for console i/o(hosted) mode
libuart.a- library for UART mode
libm.a- math library
librt.a- ewl runtime library containing ARM specific runtime support.

EWL sources are present at [CW Install Dir]/MCU/ARM_GCC_Support/ewl. User can rebuild library using existing makefiles. This can be done in two ways.