AD7885AAP Analog Devices Inc, AD7885AAP Datasheet - Page 13

• Manufacturer Part Number: AD7885AAP
• Description: IC ADC 16BIT SAMPLING HS 44-PLCC
• Manufacturer: Analog Devices Inc

Specifications of AD7885AAP

• Rohs Status: RoHS non-compliant
• Number Of Bits: 16
• Sampling Rate (per Second): 166k
• Data Interface: Parallel
• Number Of Converters: 2
• Power Dissipation (max): 325mW
• Voltage Supply Source: Dual ±
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 44-PLCC

REV. E
AD7884 to 80286 Interface
The 80286 is an advanced high performance processor with
special capabilities aimed at multiuser and multitasking systems.
Figure 19 shows an interface configuration for the AD7884 to
such a system. Note that only signals relevant to the AD7884
are shown. For the full 80286 configuration, refer to the iAPX
286 data sheet (Basic System Configuration).
In Figure 19 conversion is started by writing to a selected
address and causing CS2 to go low. When conversion is complete,
BUSY goes high and initiates an interrupt. The processor can
then read the conversion result.
82284 CLOCK
GENERATOR
CLK
Figure 19. AD7884 Interfacing to Basic iAPX 286 System
CLK
CLK
CONTROLLER
82288 BUS
D
80286
CPU
15
–D
A23–A0
MRDC
0
–13–
TRANSCEIVER
8286 OR 8287
AD7885 to 8088 Interface
The AD7885, with its byte (8 + 8) data format, is ideal for use
with the 8088 microprocessor. Figure 20 is the interface diagram.
Conversion is started by enabling CSA. At the end of conversion,
data is read into the processor. The read instructions are:
CIRCUITRY
CONTROLLER
DECODE
8282 OR
INTERRUPT
LATCH
8283
8259A
CS1
CS2
MEMORY READ
8088
AD7–AD0
MOV AX, C001 Read 8 MSBs of data
MOV AX, C000 Read 8 LSBs of data
A15–A8
Figure 20. AD7885 to 8088 Interface
MN/MX
IR
IO/M
ALE
0
RD
–IR
7
8282
STB
5V
DATA BUS
RD
CS
CONVST
DB15
DB0
DECODE LOGIC
ADDRESS BUS
AD7884
ADDRESS
BUSY
CSB
AD7884/AD7885
CSA
CONVST
CS
RD
DB7–DB0
AD7885
HBEN
A0