Logging

Table of Contents

• Overview
• Logging text and variables
• Viewing a memory block
• Usage

Overview

QuarkTS++ includes the qOS::logger class that implements application-level logging. This provides logging APIs based on C++-style streams and various helper macros. You can log a message by simply streaming things to logger::out(<a particular severity level>), e.g.. Messages can be simple text or the value of variables in specific base formats.

To use the qOS::logger class, a single-char output function must be defined using the logger::setOutputFcn() function.

A single-char output function should follow this prototype:

void SingleChar_OutputFcn ( void *sp , const char c ) {
    /* TODO : print out the c variable using the
     * selected peripheral.
     */
}

The body of this user-defined function should have a hardware-dependent code to print out the c variable through a specific peripheral.

Logging text and variables

qOS::logger::out() is the api that should be called every time the end user needs to write an entry to the log

We can configure the output with whatever severity levels we deem appropriate, including : info, warning, error and fatal. And also the debug and verbose can be used to provide additional source-location information.

Viewing a memory block

For tracing memory from a specified target address, you should use the qOS::logger::mem() specifier to define the number of bytes to be visualized of the memory block that should be given after as a pointer.

Usage

In the example below, an UART output function is coded to act as the printer. Here, the target MCU is an ARM-Cortex M0 with the UART1 as the selected peripheral for this purpose.

int main( void ) {
    uint16_t block[ 4 ] = { 451, 477, 1025, 354 };
    float other = 4.5f;
 
    logger::setOutputFcn( putUART1 );
    logger::out() << logger::mem( sizeof(block) ) << block << logger::endl;
    logger::out() << logger::mem( sizeof(float) ) << &other << logger::endl;
}

void putUART1 ( void *sp , const char c ) {
    /* hardware specific code */
    UART1_D = c;
    while ( !( UART1_S1 & UART_S1_TC_MASK ) ) {} /*wait until TX is done*/
}

As seen above, the function follows the required prototype. Later, in the main thread, a call to qOS::trace::setOutputFcn() is used to set up the output-function.

int main( void ) {
    logger::setOutputFcn( putUART1 );
    ...
    ...
}

After that, trace macros will be available for use.

void IO_TASK_Callback ( event_t e ) {
    static uint32_t Counter = 0;
    float Sample;
    ...
    ...
    logger::out() << "IO TASK running..." << logger::endl;
    Counter++;
    logger::out() << Counter << logger::endl;
    Sample = SensorGetSample ();
    logger::out() << Sample << logger::endl;
    ...
    ...
}