I have discovered that BCM21 does not have pull-up resistor or at least not one controllable with the pigpio library. Is that some known fact which I have found hard to find? Or is there something working in the background preventing me to set the pull-ups?
For example how I see that BCM10 has pull-up capabilities:
pi@testpi:~ $ pigs r 20
0
pi@testpi:~ $ pigs pud 20 u
pi@testpi:~ $ pigs r 20
1
And how BCM21 doesn't have:
pi@testpi:~ $ pigs r 21
0
pi@testpi:~ $ pigs pud 21 u
pi@testpi:~ $ pigs r 21
0
Using Raspberry Pi 3 Model B V1.2