SB16C1054_Data Sheet_EN

SB16C1054
QUAD UART WITH 256-BYTE FIFO
FEBRUARY 2009 REV 1.0
5
37
the number of data received in RX FIFO at the first time
is less than the value of FUR, or it means the number of
data in RX FIFO was more than the value of FUR and
after the CPU read them, the number of data that
remains unread after the CPU read the data received in
RX FIFO is less than or equal to the value of FLR. That
is, UART transmits Xon character to report external
device that it can receive more data.
1 : It shows that the number of data received in RX FIFO
exceeds the value of FUR and transmitting Xoff
character to report external device that it cannot receive
more data. If RX FIFO has space to store more data,
new data are stored in RX FIFO but after it gets full, they
are lost.
For more details, refer to
‘
6.3 Software Flow Control
’
.
3:2 FSR[3:2] Not used, always ‘00’.
1 FSR[1] RX Hardware Flow Control Status.
0 : When FIFO or Auto-CTS flow control is disabled.
If FIFO and Auto-CTS flow control is enabled, ‘0’ is
inputted in CTS# pin and it means external device can
receive more data. This time data in TX FIFO are
transmitted.
1 : If FIFO and Auto-CTS flow control is enabled, ‘1’ is
inputted in CTS# pin and it means external device can
not receive more data. This time data in TX FIFO are not
transmitted.
For more details, refer to ‘6.2 Hardware Flow Control’.
0 FSR[0] RX Software Flow Control Status.
0 : When FIFO or RX Software flow control is disabled.
If FIFO and RX Software flow control is enabled, it
means Xoff character has never arrived or Xon character
arrived after Xoff character had arrived(it means external
device can receive more data). This time data in TX FIFO
are transmitted.
1 : If FIFO and RX Software flow control is enabled, it means
Xoff character has arrived and external device can not
receive data any more. This time characters in TX FIFO are
not transmitted.
For more details, refer to ‘6.3 Software Flow Control’.