TVREFINT Internal reference startup time - - 2-3 ms

[CDesh]

Hi,

From the data sheet of STM32L072xx it is mentioned that Tvrefint start up time is 2-3msec. When using Vrefint in comparator, does controller take 2-3msec each time to compare input with Vrefint or it is just the initial start up time?

Because I have been observing that though the Vrefint is always enabled, comparator is taking 3-4msec each time to compare input with Vrefint.

Please clarify.

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TVREFINT Internal reference startup time - - 2 3 ms

[waclawek.jan]

> comparator is taking 3-4msec each time to compare input with Vrefint.

How exactly do you measure that?

JW

[CDesh]

I am giving input signal of 4msec duration, below which the comparator is not comparing with Vrefint.

So the comparator takes 3-4msec each time to compare? Kindly confirm, how do you say so?

[waclawek.jan]

Do you change the COMP configuration dynamically, i.e. during the run of the program?

What is the content of REF_CFGR3 and PWR_CR registers?

Do you use some of the low power modes?

JW

[CDesh]

Yes, I am enabling comparator during MCU start-up and triggering signal of 3-4msec duration in SLEEP mode. Please note that I am not disabling comparator and it is ON forever once the MCU is started.

SYSCFG_CFGR3_VREFINT_RDYF - 40000000

PWR_CSR_VREFINTRDYF - 8

PWR_CR_UPL - 200