2021-02-27 10:01 AM
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
2021-02-27 12:20 PM
> comparator is taking 3-4msec each time to compare input with Vrefint.
How exactly do you measure that?
JW
2021-02-27 05:11 PM
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?
2021-03-01 07:24 AM
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
2021-03-01 08:30 PM
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