SERIAL node stopbits problem

I found a problem with SERIAL node (Raspberry PI Zero W hardware /dev/ttyS0). It doesn't react to stopbits value.
I've made 2 oscillograms with 1 stopbit (top) and 2 stopbits(bottom) and it looks absolutely the same.

Maybe who knows, how to fix this problem.

Is that the pi sending data or receiving? That may sound like a silly question but it has to be asked.

pi sending data.

Most odd. we set up the serialport here -
and at that point we do pass on 1 or 2 correctly - so if there really is a problem it must be with the underlying library which I would be surprised about (given it is so widely used) but...

As I see you do correct setup in 25-serial.js

this.stopbits = parseInt(n.stopbits) || 1;

I tried to set it 2 directly, but haven't got any effect.

I just wondered why it doesn't work? In the .cpp library file, I see 1bit, 1.5bits, and 2bits for stopbits.

SerialPortStopBits NAN_INLINE(ToStopBitEnum(double stopBits)) {
if (stopBits > 1.4 && stopBits < 1.6) {
if (stopBits == 2) {

I found how to solve it!

I use tty/AMA0 instead tty/S0.