maximum baudrate on uart in half-duplex mode

[dh_leslie]

I am using uart on STM32L07 to simulate 1-wire for operating ds28e22. 1-bit timing is more than 1us and less than 2us. When I set baudrate at 666666 which meant 1 bit timing was 1.5us, I found the rising edge was too slow (more than 1 us). So I want to know what's maximum rate for uart under half-duplex mode.

thanks.

[KnarfB]

The baud rate is internally generated from the UART clock. If the clock rate is too low, the baud rate will be off. 

How did you measure "the rising edge"? 

hth

KnarfB