XR88C681J-F Exar Corporation, XR88C681J-F Datasheet - Page 14

• 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

B.1 DUART Register Addressing
The addressing of the internal registers of the DUART is presented in Table 1. Please note that some of the
registers are “Read Only” and others are “Write Only”. Each channel is provided with the following dedicated
(addressable) registers.
D Command Registers
D Mode Registers (MR1 and MR2)
D Status Registers
D Clock Select Registers
D Receiver Holding Register (RHR) and Transmit Holding Register (THR)
Additionally, the DUART contains the following registers that support/control both channels.
D Interrupt Status Register
D Interrupt Mask Register
D Masked Interrupt Status Register
D Interrupt Vector Register
D Auxiliary Control Register
And finally, the DUART also contains other registers that support functions other than serial data communication, such
as the parallel ports and the counters/timers.
D OPCR- Output Port Control Register
D IPCR - Input Port Configuration Register
D CTUR - Counter/Timer Upper Byte Register
D CTLR - Counter/Timer Lower Byte Register
Rev. 2.11
E clock
-RESET
-R/W
Figure 2. External Logic Circuitry required to interface a 6800 Family
Processor to the XR88C681 Device
14
-WR
-RD
RESET