12-BIT µP-COMPATIBLE
ANALOG-TO-DIGITAL CONVERTERS
TC7109
TC7109A
Direct interfacing to most microprocessor busses is
easily accomplished through the three-state output of the
TC7109A.
Figures 1, 17 and 18 are typical connection diagrams.
To ensure requirements for setup and hold times, minimum
pulse widths, and the drive limitations on long busses are
met, it is necessary to carefully consider the system timing
in this type of interface. This type of interface is used when
the memory peripheral address density is low, providing
simple address decoding. Interrupt handling can be simpli-
fied by using an interface to reduce the component count.
CHIP SELECT 1
CHIP SELECT
GND
A. GND
B. GND
C.
MODE CE/LOAD
MODE
CE/LOAD
MODE CE/LOAD
B9–B12
POL, OR
B9–B12
POL, OR
6
6
B1–B12
POL, OR
14
TC7109A
B1–B8
TC7109A
TC7109A
B1–B8
8
8
ANALOG
IN
ANALOG
IN
ANALOG
IN
RUN/HOLD
RUN/HOLD
RUN/HOLD
CONVERT
CONVERT
CONVERT
HBEN
LBEN
HBEN
LBEN
HBEN
LBEN
GND OR
CHIP SELECT 2
CONTROL
BYTE FLAGS
Figure 12. Direct Mode Chip and Byte Enable Combinations
CONVERTER
SELECT
CONVERTER
SELECT
CONVERTER
SELECT
GND
GND
GND
MODE CE/LOAD
MODE CE/LOAD
MODE CE/LOAD
B9–B12
B9–B12
B9–B12
6
8
6
8
6
POL, OR
POL, OR
POL, OR
TC7109A
B1–B8
TC7109A
B1–B8
TC7109A
B1–B8
8
ANALOG
IN
ANALOG
IN
ANALOG
IN
RUN/HOLD
RUN/HOLD
RUN/HOLD
+5V
+5V
+5V
HBEN
LBEN
HBEN
LBEN
HBEN
LBEN
BYTE SELECT FLAGS
Figure 13. Three-Stating Several TC7109A's to a Small Bus
3-106
TELCOM SEMICONDUCTOR, INC.
TELCOM [ TELCOM SEMICONDUCTOR, INC ]
