Upper Threshold / Lower Threshold

Upper Threshold

This register configures the upper threshold of the receive FIFO buffer. If the number of free bytes in the receive FIFO buffer exceeds this upper threshold, the reception status is set to active. This means, for example, that depending on the handshake configuration an XON character is sent, or the RTS line is set to active.

Lower Threshold

This register configures the lower threshold of the receive FIFO buffer. If the number of free bytes in the FIFO buffer undershoots the lower threshold, the reception status is set to passive. This means, for example, that depending on the handshake configuration an XOFF character is sent, or the RTS line is set to passive.