SB16C1054PCI_Data Sheet_EN

SB16C1054PCI

PCI Target Interface Controller

with Quad-UART

JULY 2013 REV 1.04

13.22 Flow Control Upper Threshold Register (FUR, Page 4)

FUR can be written only when 256-byte FIFO mode is enabled and one of TX software

flow control or Auto-RTS is enabled (In 64-byte mode, it cannot be written but can be

read only, and follows the value of trigger level set in FCR[5:4]). While TX software flow

control is enabled, Xoff character is transmitted when the number of data in RX FIFO

exceeds the value of FUR. If Auto-RTS is enabled, 1b is outputted on RTS# pin to

report that it cannot receive data any more. If both TX software flow control and Auto-

RTS is enabled, Xoff character is transmitted and 1b is outputted on RTS# pin. The

value of FUR must be larger than that of FLR.

13.23 Flow Control Lower Threshold Register (FLR, Page 4)

FLR can be written only when 256-byte FIFO mode is enabled and one of TX software

flow control, or Auto-RTS is enabled (In 64-byte mode, it cannot be written but can be

read only, and follows the value of trigger level set in FCR[7:6]). While TX software flow

control is enabled, Xon character is transmitted when the number of data in RX FIFO is

less than the value of FUR only if Xoff character is transmitted before. If Auto-RTS is

enabled, 0b is outputted on RTS# pin to report that it can receive more data. If both TX

software flow control and Auto-RTS is enabled, Xon character is transmitted only if Xoff

character is transmitted before and 0b is outputted on RTS# pin. The value of FLR must

be less than that of FUR.