3-106

TELCOM SEMICONDUCTOR, INC.

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.

TC7109A

MODE

CE/LOAD

B9–B12

POL, OR

B1–B8

LBEN

HBEN

GND

8

ANALOG

IN

6

CONVERT

CONTROL

RUN/HOLD

TC7109A

MODE

CE/LOAD

B1–B12

POL, OR

LBEN

HBEN

GND

ANALOG

IN

CONVERT

RUN/HOLD

TC7109A

MODE

CE/LOAD

B9–B12

POL, OR

B1–B8

LBEN

HBEN

8

ANALOG

IN

6

CONVERT

RUN/HOLD

CHIP SELECT 1

GND OR

CHIP SELECT 2

14

BYTE FLAGS

GND

CHIP SELECT

A.

B.

C.

Figure 12. Direct Mode Chip and Byte Enable Combinations

TC7109A

MODE

CE/LOAD

B9–B12

POL, OR

B1–B8

LBEN

HBEN

GND

8

ANALOG

IN

6

RUN/HOLD

+5V

CONVERTER

SELECT

TC7109A

MODE

CE/LOAD

B9–B12

POL, OR

B1–B8

LBEN

HBEN

GND

8

ANALOG

IN

6

RUN/HOLD

+5V

TC7109A

MODE

CE/LOAD

B9–B12

POL, OR

B1–B8

LBEN

HBEN

GND

8

ANALOG

IN

6

RUN/HOLD

+5V

CONVERTER

SELECT

CONVERTER

SELECT

BYTE SELECT FLAGS

Figure 13. Three-Stating Several TC7109A's to a Small Bus

TC7109

TC7109A

12-BIT

ANALOG-TO-DIGITAL CONVERTERS