Hello,
Did you tried to run it (without debugging)?
I've tested this example by using TWR-K21D50M but using the external reference clock from TWR-SER instead of 8-MHz resonator and it worked well. This is the code that I used:
int main(void) {
/* Init board hardware. */
BOARD_InitPins();
//BOARD_BootClockRUN();
BOARD_InitDebugConsole();
/* Add your code here */
PRINTF("Loss of Clock test!\r\n");
/* Add your code here */
osc_config_t oscConfig;
oscConfig.freq = 50000000;
oscConfig.capLoad = 0U;
oscConfig.workMode = kOSC_ModeExt;
oscConfig.oscerConfig.enableMode = 0;
CLOCK_InitOsc0(&oscConfig);
CLOCK_SetXtal0Freq(oscConfig.freq);
PRINTF("OSC init OK\r\n");
PRINTF("Moving to FEE.....");
/* Set clock divider to safe value to switch mode */
CLOCK_SetSimSafeDivs();
CLOCK_SetFeeMode(6, kMCG_Dmx32Default, kMCG_DrsMid, NULL);
g_bFeiModeOn = 0;
DbgConsole_Deinit();
BOARD_InitDebugConsole();
PRINTF("OK\r\n");
PRINTF("Core is running at %d Hz\r\n", CLOCK_GetCoreSysClkFreq());
CLOCK_SetOsc0MonitorMode(kMCG_MonitorInt);
NVIC_EnableIRQ(MCG_IRQn);
for (;;) { /* Infinite loop to avoid leaving the main function */
if (g_bFeiModeOn)
{
delay();
g_bFeiModeOn = 0;
CLOCK_SetFeeMode(6, kMCG_Dmx32Default, kMCG_DrsMid, NULL);
DbgConsole_Deinit();
BOARD_InitDebugConsole();
CLOCK_SetOsc0MonitorMode(kMCG_MonitorInt);
NVIC_EnableIRQ(MCG_IRQn);
PRINTF("Core is running at %d Hz\r\n", CLOCK_GetCoreSysClkFreq());
}
/* something to use as a breakpoint stop while looping */
}
}
void MCG_IRQHandler(void) {
CLOCK_SetOsc0MonitorMode(kMCG_MonitorNone);
NVIC_DisableIRQ(MCG_IRQn);
PRINTF("Returning to FEI mode");
CLOCK_SetFeiMode(kMCG_Dmx32Default, kMCG_DrsLow, NULL);
g_bFeiModeOn = 1;
DbgConsole_Deinit();
BOARD_InitDebugConsole();
PRINTF("Core is running at %d Hz\r\n", CLOCK_GetCoreSysClkFreq());
}When I debugged the project, I also could see that IREFST field of register MCG_S remains set to '0' but when I ran and used debug console I could see that transitions where done correctly.
I hope this helps!
Regards,
Isaac
