xr88c681 Exar Corporation, xr88c681 Datasheet - Page 34

• Manufacturer Part Number: xr88c681
• Description: Cmos Dual Channel Uart Duart
• Manufacturer: Exar Corporation

Figure 11 presents a schematic where the DUART will request a “External-Vectored” Interrupt to the 8085 CPU. In this
case, the Interrupt Service Routine for the DUART must begin at 0020
Rev. 2.11
8085 CPU
Figure 10. The XR88C681/8085 CPU Interface for Direct Interrupt Processing
AD0 - AD7
A15 - A8
(Interrupt Service Routine is located at 0034
RST 6.5
-IO/M
ALE
-WR
-RD
74LS373
D
C
34
Address Decoding
Q
Logic
-MEMR
-MEMW
-IOR
-IOW
A7 - A4
16
16
in system memory.
V
in System Memory)
cc
-INTR
D0 - D7
A0 - A3
-CS
-RD
-WR
XR88C681