UART device -- stop bits setting?

[Guest]

Hi,

I've been toying with the DigitalUart API.

The FDwfDigitalUartTxSet allows the setting of the number of stop bits. Its parameter is of type double, which makes sense; some (old) serial devices specify a non-integer number of stop bits, in particular 1.5 stop bits is something that you could come across in real life (well back in the 1970s anyway).

However, I did some tests and this is not what at least the TX-side does. The number of TX-side stop-bits, i.e., the pause between the last data-bit and the next character's start bit seems to be equal to ceiling(stopbits).

Which leads to my question: does the RX-side actually honor non-integer stop-bit counts? (I could do an experiment but it's a bit tiresome).

If not, then the "double" type is a bit unfortunate, because it suggests a behavior that is not really there. Unfortunately, the documentation is too sparse on this to tell if the API intends to support things like 1.5 stop bits.

[attila]

Hi @reddish

The current devices (firmware/hdl) support only integer stops, half will be rounded up like 1.5 to 2
The stop is a double parameter for eventually supporting half stops on a future device.

[Guest]

Okay thanks, that explains it.