AD671KD-500 AD [Analog Devices], AD671KD-500 Datasheet - Page 14

• Manufacturer Part Number: AD671KD-500
• Description: Monolithic 12-Bit 2 MHz A/D Converter
• Manufacturer: AD [Analog Devices]

AD671
AD671 TO ADSP-2100A INTERFACE
Figure 19 demonstrates the AD671 to ADSP-2100A interface.
The 2100A with a clock frequency of 12.5 MHz can execute an
instruction in one 80 ns cycle. The AD671 is configured to per-
form continuous time sampling. The DAV output of the AD671
is asserted at the end of each conversion. DAV can be used to
latch the conversion result into the two 574 octal D-latches. The
falling edge of the sampling clock is used to generate an inter-
rupt (IRQ3) for the processor. Upon interrupt, the ADSP-
2100A starts a data memory read by providing an address on
the DMA bus. The decoded address generates OE for the
latches and the processor reads their output over the DMA bus.
The conversion result is read within a single processor cycle.
AD671 TO ADSP-2101/ADSP-2102 INTERFACE
Figure 20 is identical to the 2100A interface except the sam-
pling clock is used to generate an interrupt (IRQ2) for the pro-
cessor. Upon interrupt the ADSP-2101A starts a data memory
read by providing an address on the Address (A) bus. The de-
code address generates OE for the D-latches and the processor
reads their output over the Data (D) bus. Reading the conver-
sion result is thus completed within a single processor cycle.
Figure 21. PCB Silkscreen and Component Placement
Diagram for Figures 5, 10 and 13
–14–
ADSP-2100A
ADSP-2101
Figure 20. AD671 to ADSP-2101/ADSP-2102 Interface
DMA0:13
DMA0:15
DMACK
Figure 19. AD671 to ADSP-2100A Interface
DMRD
A0:13
D0:15
IRQ3
IRQ2
RD
ADDRESS BUS
ADDRESS BUS
DECODE
DECODE
+ 5V
16
16
DATA BUS
DATA BUS
SAMPLING
SAMPLING
CLOCK
CLOCK
8
8
8
8
OE
Q0:7
OE
Q0:7
OE
Q0:7
OE
Q0:7
574
574
574
574
D0:7
D0:3
D0:7
D0:7
D0:3
D0:7
4
4
4
4
8
8
DAV
BIT1:12
DAV
BIT1:12
ENCODE
ENCODE
AD671
AD671
REV. B