S
hDear LPC55xx support,
Customer : I-Blades.
I-blades was looking at the lpadc sample code to figure out how the calibration code works .After stepping through the code they realize that the sample code does not actual go thru the calibration procedure but simply writes to fixed values of 10 into the calibration offset register.
Q: Are those values specific for the eval Board ?
Snippet of Calibration code:
#if defined(FSL_FEATURE_LPADC_HAS_CTRL_CALOFS) && FSL_FEATURE_LPADC_HAS_CTRL_CALOFS
#if defined(FSL_FEATURE_LPADC_HAS_OFSTRIM) && FSL_FEATURE_LPADC_HAS_OFSTRIM
/* Request offset calibration. */
if (true == DEMO_LPADC_DO_OFFSET_CALIBRATION)
{
LPADC_DoOffsetCalibration(DEMO_LPADC_BASE);
}
else
{
LPADC_SetOffsetValue(DEMO_LPADC_BASE, DEMO_LPADC_OFFSET_VALUE_A, DEMO_LPADC_OFFSET_VALUE_B);
}
#endif /* FSL_FEATURE_LPADC_HAS_OFSTRIM */
/* Request gain calibration. */
LPADC_DoAutoCalibration(DEMO_LPADC_BASE);
#endif /* FSL_FEATURE_LPADC_HAS_CTRL_CALOFS */
if you use the debugger and step thru this code you will see that the line :
LPADC_SetOffsetValue(DEMO_LPADC_BASE, DEMO_LPADC_OFFSET_VALUE_A, DEMO_LPADC_OFFSET_VALUE_B);
is the only line that is executed.
As you can see from the code below the LPADC_DoAutoCAlibration is greyout by the #if Defined at the top so there is no auto calibration taken place.
Q: what is the reason for not calling the auto calibration in the demo code?
Q: If the customer want to use this calibration for his own board, can he just call it?
hi XiangJun Rong,
i added the code into both interrupt and polling code, but when i ran it, it keep getting stuck on this while loop right here.
(See below screen capture).
Please advise!
Hi, HyMai,
I think you can download the latest SDK package based on LPC55S69 SDK_2.6.3_LPCXpresso55S69.zip and use the latest MCUXpresso tools ver11.0.1, and load the lpadc_interrupt example. You do not need to change anything, it do calibration exactly without any modification.
I have tried to debug, this is the result. of course, I can pass the calibration.
BR
XiangJun Rong
