XR88C681J-F Exar Corporation, XR88C681J-F Datasheet - Page 79

• Manufacturer Part Number: XR88C681J-F
• Description: IC UART CMOS DUAL 44PLCC
• Manufacturer: Exar Corporation
• Type: CMOS Dual Channel UARTr

Specifications of XR88C681J-F

• Number Of Channels: 2, DUART
• Package / Case: 44-LCC (J-Lead)
• Features: *
• Fifo's: 1 Byte, 3 Byte
• Voltage - Supply: 5V
• With Parallel Port: Yes
• With Cmos: Yes
• Mounting Type: Surface Mount
• Data Rate: 1 Mbps
• Supply Voltage (max): 5.25 V
• Supply Voltage (min): 4.75 V
• Supply Current: 15 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 5 V
• Propagation Delay Time Ns: 400 ns
• No. Of Channels: 2
• Supply Voltage Range: 4.75V To 5.25V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: PLCC
• No. Of Pins: 44
• Filter Terminals: SMD
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 1016-1329

H. SPECIAL MODES OF OPERATION
H.1 RTS/CTS Handshaking
The DUART can be programmed to support RTS/CTS
Handshaking, as a means of data flow control with other
devices. This section will describe a couple of options that
the DUART allows the user in implementing RTS/CTS
Handshaking. Specifically, these options are:
D Receiver-Controlled RTS/CTS Handshaking
D Transmitter-Controlled RTS/CTS Handshaking
Rev. 2.11
FFULLA
RXDA
RTSA
Figure 42. Block Diagram and Timing Sequence of Two DUARTs Connected
Receiving Device
To CPU
FFULLA
(OP4)
in the Receiver-RTS Controlled Configuration
RTSA
RXDA
CTSA
(OP0)
TXDA
(IP0)
79
H.1.1 Receiver-Controlled RTS/CTS Handshaking
In this mode, the Receiver has the ability to automatically
negate the RTS output (to the Transmitting device).
Specifically, this mode allows the Receiver to negate the
RTS signal if its RHR is full; and, is thereby, very effective
in preventing Receiver Overrun Errors.
presents a diagram of an example illustrating the
operation of the Receiver-Controlled RTS configuration.
CTSB
(IP1)
TXDB
RXDB
RTSB
(OP1)
Transmitting Device
XR88C681
Figure 42