xr82c684 Exar Corporation, xr82c684 Datasheet - Page 35

• Manufacturer Part Number: xr82c684
• Description: Cmos Quad Channel Uart Quart
• Manufacturer: Exar Corporation

Interfacing the 8080 CPU Module to the XR82C684
QUART for Interrupt Processing
only includes information pertaining to QUART interrupt
Table 7. 8080A and 8085 CPU Restart Instructions
Op-Code (hex)
Used with Vectored Interrupts
Mnemonic
Table 7
Please note that Figure 11
Figure 11
Restart Address
(hex)
servicing.
Generator, the Address Bus, etc.) have been omitted from
the schematic. In this schematic, the QUART Interrupt
Service Routine is located at 0020
Additionally, the QUART has been configured to operate
in the I-Mode. The function description of this circuit is
presented below.
example, the value “E7
U3. This value is the op-code for the “RST 4” command.
Hence, once this data is gated into the CPU module, via
the data bus, the CPU will load 0020
Counter and branch program control to that location. The
Interrupt Service Routine for the QUART exists at this
location in memory.
Other circuitry (such as the 8224 Clock
16
” is hard-wired into the input of
XR82C684
Please note that, in this
16
16
into its Program
in memory.