topic Re: LPC82x Brownout Detection in LPC Microcontrollers

LPC82x Brownout Detection

mwp_nxp — Thu, 10 Oct 2024 06:21:11 GMT

Hi all,

POWER_SetBodLevel(kBod_ResetLevel1, kBod_InterruptLevel2, true);
EnableIRQ(BOD_IRQn);

When VCC drops below 2.54V, the Int is triggered.

How do i detect when VCC has returned back above 2.54V?

Also, the LPC82x user manual on page 56 states in relation to BOD:

The interrupt signal can be enabled for interrupt in the Interrupt Enable Register in the
NVIC (see Table 6) in order to cause a CPU interrupt; if not, software can monitor the
signal by reading a dedicated status register.

What is the status register that is mentioned? I cannot find any mention of it anywhere else.

Thanks in advance.

Re: LPC82x Brownout Detection

xiangjun_rong — Fri, 11 Oct 2024 02:47:36 GMT

Hi,

I suppose the UM10800.pdf is incorrect, there is not dedicated BOD status register for LPC82x family, there is not the BOD state bit which you can poll.

But there is BOD Reset status bit in SYSCON->STARTERP1[BOD], with which you can poll the register to know which has reset the chip.

Hope it can help you

XiangJun Rong

Re: LPC82x Brownout Detection

mwp_nxp — Fri, 11 Oct 2024 03:49:49 GMT

Is there a method to detect when VCC has risen back above the BODINTVAL level?

Re: LPC82x Brownout Detection

xiangjun_rong — Fri, 11 Oct 2024 04:10:39 GMT

Hi,

I have not good idea to test the VDD voltage.

As you know that the LPC82x has ADC, if you connect the VDD to ADC analog channel, the ADC sample is effected by the VREFP/VDD voltage.

If you use on-chip ACMP module, the VDD also takes effect on the ACMP output.

Xiangjun Rong