XR88C681J-F Exar Corporation, XR88C681J-F Datasheet - Page 43

• 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

Z-80 CPU Interrupt Servicing Capability
The Z-80 CPU contains two interrupt request pins:
and
input pin; and
input pin. For the sake of interfacing to the DUART, we are
only concerned with the
The Z-80 CPU can be configured to operate in one of
three different interrupt modes:
D External Vectored
D Direct
D “Peripheral” Vectored
-
Rev. 2.11
INT.
-
NMI is the “Non-Maskable” interrupt request
Clock input
-
INT is the “Maskable” interrupt request
-
INT pin.
Figure 18. Schematic of Z-80 CPU Module
GND
+5V
PHI
-INT
-NMI
-WAIT
-BUSRQ
-HALT
-RFSH
-BUSAK
-RESET
A0 - A15
D0 - D7
-MREQ
-IORQ
-WR
-RD
-M1
-
NMI
43
Each of these interrupt modes use the
CPU and will be discussed in the following sections.
External Vectored Interrupt Processing (Interrupt
Mode 0)
The Z-80 P will operate in this interrupt mode if the “IM 0”
instruction has been executed. Whenever the
asserted by a peripheral device requesting an interrupt,
the CPU will complete its current instruction.
completion of this instruction, the CPU module will assert
-
Acknowledge” signal that the CPU module outputs in
order to initiate the process of interrupt servicing. When
the Z-80 CPU operates in the Interrupt Mode 0, it is
INTA (toggle “low”).
-
INTA is the active-low “Interrupt
XR88C681
-MEMW
-MEMR
-IOW
-INTA
-IOR
-
INT pin of the Z-80
-
INT pin is
After