Integrating analog-to-digital converters (ADCs) featuring binary-
coded decimal (BCD) outputs for display interface offer a number
of excellent features, as well as high resolution, at a very low cost.
These advantages include auto-zeroing, sign-magnitude coding,
noise averaging, and high impedance inputs and are also attrac-
tive for microprocessor-based systems. Unfortunately, many
display-oriented ADCs are difficult to interface due to the multi-
plexed BCD format of the outputs. An exception is the 4-1/2 digit
TC7135 ADC, which provides a "strobe" output. AN785
Simplify A/D Converter Interface with Software
Authors: Gary Grandbois and Wes Freeman,
INTERFACE HARDWARE
Microchip Technology, Inc. The complete TC7135-to-18255A hardware interface is shown in
Figure 1. The only digit strobe used is DS5 (MSD), and the BUSY
output is ignored. To understand why the other digit strobes are not
INTRODUCTION ……
