XR88C681_06 Datasheet, PDF (81/101 Pages) Exar Corporation – CMOS Dual Channel UART (DUART)

XR88C681
For Receiving Device
MR1A[7] = 1
For Transmitting Device
MR2B[7] = 1
Start
Assert RTSA
Write 01h to QUART Address 0Eh
(This invokes the “SET OUTPUT
PORT BITS COMMAND” and sets
the Output Port pin, OP0 to a logic
“0”.)
Is
No
FFULLA
Asserted?
Yes
RTSA is Automatically
Negated by Receiver
Controlled RTS Function.
No
Is
FFULLA
Yes
Negated?
Figure 43. A Flow Diagram Depicting an Algorithm That Could be Used to Apply
the Receiver-Controlled RTS/CTS Handshaking Mode
H.1.2 Transmitter-Controlled RTS/CTS Handshaking
In this mode, the Transmitter now has the ability to negate the RTS output (to the Receiving Device). Specifically, this
mode allows the Transmitter to negatye the RTS signal, one bit period after emptying the THR and TSR.
Rev. 2.11
81