LPCOMP/COMP problem of NRF52832

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Hi I'm working on detecting voltage change direction(up or down) by using LPCOMP or COMP. LPCOMP initiates as following settings: detection: NRF_LPCOMP_DETECT_UP. reference: NRF_LPCOMP_REF_SUPPLY_11_16.

Toggle the detection direction in the LPCOMP IRQ handler by uninit LPCOMP and re-init it.

Like the picture showing:

Case 1 Selector selects GND Disconnect the switch, the input voltage to LPCOMP changes from GND to ~3.0v. Connect the switch , the input voltage to LPCOMP changes from ~3.0v to GND. In this case the LPCOMP working well.

Case 2 Selector selects 1.8v (Reference chip output). Disconnect the switch, the input voltage to LPCOMP changes from 1.8v to ~3.0v. Connect the switch , the input voltage to LPCOMP changes from ~3.0v to 1.8v. In this case, regardless, which state of the switch is in, the the LPCOMP won't generate any interrupt.

I have tried to use COMP Single End mode to be instead, I got the same problem. It seems to be if the voltage change range become narrow on VIN+, then the LPCOMP/COMP stops working.

Please help me to correct the problem.

[FormerMember]

In case 2, what does your code for setting up the LPCOMP look like?

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Hi Kristin,

Case 2, my init settings for LPCOMP : direction is NRF_LPCOMP_DETECT_UP and reference is NRF_LPCOMP_REF_SUPPLY_11_16. And in the LPCOMP irq handler, the direction will be changed to an opposite side by doing uninit and re-init. By the way, I am using SDK11 and softdevice is 2.0.0 (S132). Is there any problem? Please correct me if I am wrong. Thanks.

[bing]

Sorry. I add the comment to a wrong position.

Case 2, my init settings for LPCOMP : direction is NRF_LPCOMP_DETECT_UP and reference is NRF_LPCOMP_REF_SUPPLY_11_16. And in the LPCOMP irq handler, the direction will be changed to an opposite side by doing uninit and re-init. By the way, I am using SDK11 and softdevice is 2.0.0 (S132). Is there any problem? Please correct me if I am wrong. Thanks.

[FormerMember]

Do you see the same problem if you test the bare lpcomp example in SDK 11 and SDK 13? (without using the softdevice)

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Yes. I tested using SDK13. It is OK. The problem is nrf_lpcomp_ref_t is wrongly defined in SDK11. NRF_LPCOMP_REF_SUPPLY_1_16 to NRF_LPCOMP_REF_SUPPLY_15_16, they are all the same( LPCOMP_REFSEL_REFSEL_Ref1_16Vdd).

Thanks.