Interrupt voltage and current

[Mike Bounds]

Posted on January 31, 2018 at 21:55

Where do I find (manual and section/table) the voltage required to set external interrupt to low and high and also the minimum and maximum current.  I am looking for this information for the STM8L152C6, so something like voltage needs to below 1v to be low and above 2V to be high and minimum current required.

Thanks

Mike

#interrupt

[Tesla DeLorean]

Posted on January 31, 2018 at 22:24

http://www.st.com/content/ccc/resource/technical/document/datasheet/43/12/db/4c/8b/08/4a/73/CD00240181.pdf/files/CD00240181.pdf/jcr:content/translations/en.CD00240181.pdf

 

Like the VIL and VIH numbers based on VDD , and Input Leakage Current?

[henry.dick]

Posted on January 31, 2018 at 23:19

The datasheet should specify input low and input high voltage thresholds . For 5v devices generally 20 and 80 percent of vdd, for St pins.

[Mike Bounds]

Posted on February 01, 2018 at 00:41

Thanks for replies - this is what I was looking for voltage, but still not sure about current - I found 'Table 38. I/O static characteristics' which shows:

VIL - Input low level voltage Max = 0.3 x VDD

VIH - Input high level voltage Min = 0.7 x VDD

So this make sense - for interrupts,  to set low, Voltage will need to be less than 30% and to set high voltage needs to be higher than 70%, but what is the min and max that the current will need to be - i.e. won't I need to put a resistor on the GPIO min to limit the current, but not limit too much so that it is too small?

[Tesla DeLorean]

Posted on February 01, 2018 at 01:26

Current is going to be negligible, load is typically quoted in capacitance, ie resistance to change. Holding a transistor in a high or low state is quoted at 200nA