Other Parts Discussed in Thread: LAUNCHXL-F280049C
The prototype of F280049 used by customer is in the process of debugging. At present, there are some problems in the use of internal 1.2V dc-dc module. I need your help to answer them.
During the test, they found that the PWM waveform in GPIO_23VSW output is not continuous, and it is intermittent, resulting in a large ripple in the voltage of output capacitor. The recommended parameters are selected for the external inductance and capacitance.
Is it normal to have intermittent phenomenon? Or is it caused by incorrect configuration of software and hardware? Thank you!
The following is the related hardware and software configuration and waveform for reference.
Software configuration:
Void InItDCDC (void)
{
EALLOW;
AnalogSubsysRegs.DCDCCTL.bit.DCDCEN=1;
While ((AnalogSubsysRegs.DCDCSTS.Bit.INDDETECT! = 1) ||(AnalogSubsysRegs.DCDCSTS.Bit.SWSEQDONE! = 1))
{/ / waiting to be set
}
EDIS;
DELAY_US(80); / / delay 80us
}
The schematic diagram of this part of our company is as follows:
The figure below shows the output of GPIO23_VSW and 1.2V waveform detected by our oscilloscope, in which the red waveform is the output of GPIO23_VSW and the green is 1.2V.
The figure below shows the output of GPIO23_VSW with pulse after expansion.
