void CCommandProcessor::BusyWait ( const char * const paramBegin )
{
const char * const delayEnd = SkipCharsNotInSet( paramBegin, SPACE_AND_TAB );
const char * const extraArgBegin = SkipCharsInSet ( delayEnd, SPACE_AND_TAB );
if ( *paramBegin == 0 || *extraArgBegin != 0 )
{
PrintStr( "Invalid arguments." EOL );
return;
}
const unsigned delayMs = ParseUnsignedIntArg( paramBegin );
if ( delayMs == 0 || delayMs > 60 * 1000 )
{
PrintStr( "Invalid arguments." EOL );
return;
}
const uint32_t oneMsIterationCount = GetBusyWaitLoopIterationCountFromUs( 1000 );
for ( uint32_t i = 0; i < delayMs; ++i )
{
BusyWaitLoop( oneMsIterationCount );
}
Printf( "Waited %u ms." EOL, unsigned( delayMs ) );
}
extern "C" void BareMetalSupport_Reset_Handler ( void )
{
SetupCpuClock();
// Delay the start-up sequence, so that an external JTAG debugger has a chance
// to stop the firmware near the beginning.
//
// How much busy wait time you need to spend here depends on how fast your JTAG adapter is.
// With my slow Bus Pirate (at 'normal' speed, instead of 'fast'), and with a non-optimised
// JtagDue firmware, I need around 34 ms. If you have a fast JTAG probe, you can probably
// lower this time in order to get faster overall boot times.
//
// If you do not need to debug the firmware from the very beginning, or if you do not place
// breakpoints somewhere during the initialisation code, then you can comment-out this busy wait.
const unsigned BUSY_WAIT_LOOP_US = 36 * 1000;
BusyWaitLoop( GetBusyWaitLoopIterationCountFromUs( BUSY_WAIT_LOOP_US ) );
// Relocate the initialised data from flash to SRAM.
const uint32_t * relocSrc = (const uint32_t *)&_etext;
uint32_t * relocDest = ( uint32_t *)&_srelocate;
if ( relocSrc != relocDest )
{
while ( relocDest < (const uint32_t *) &_erelocate )
{
*relocDest++ = *relocSrc++;
}
}
// Clear the zero segment (BSS).
for ( uint32_t * zeroSegPtr = (uint32_t *)&_szero; zeroSegPtr < (const uint32_t *) &_ezero; ++zeroSegPtr )
{
*zeroSegPtr = 0;
}
// Set the vector table base address.
const uint32_t * const pVecSrc = (const uint32_t *) & _sfixed;
SCB->VTOR = ((uint32_t) pVecSrc & SCB_VTOR_TBLOFF_Msk);
if (((uint32_t) pVecSrc >= IRAM0_ADDR) && ((uint32_t) pVecSrc < NFC_RAM_ADDR))
{
SCB->VTOR |= (1UL) << SCB_VTOR_TBLBASE_Pos;
}
// The CPU starts at 4 MHz, and that should be the default value of variable SystemCoreClock.
// We have set the CPU clock above, so update this variable here. Its value is needed
// in order to calculate the clock delay to get the correct UART speed.
assert( SystemCoreClock == 4000000 );
SystemCoreClockUpdate();
#ifndef NDEBUG
assert( SystemCoreClock == CPU_CLOCK );
assert( SystemCoreClock == CHIP_FREQ_CPU_MAX );
#endif
// Initialize the C/C++ support by calling all registered constructors.
__libc_init_array();
// From this point on, all C/C++ support has been initialised, and the user code can run.
RunUserCode();
// If you want to check for memory leaks and so on, you may need to call the destructors here:
// __libc_fini_array();
Panic("RunUserCode() returned unexpectedly.");
}