MC68HC16Z1 Datasheet, PDF (187/500 Pages) Freescale Semiconductor, Inc – M68HC16Z Series

Freescale Semiconductor, Inc.
SECTION 8
ANALOG-TO-DIGITAL CONVERTER
This section is an overview of the analog-to-digital converter module (ADC). Refer to
the ADC Reference Manual (ADCRM/AD) for a comprehensive discussion of ADC ca-
pabilities. Refer to APPENDIX A ELECTRICAL CHARACTERISTICS for ADC timing
and electrical specifications. Refer to D.5 Analog-to-Digital Converter Module for
register address mapping and bit/field definitions.
8.1 General
The ADC is a unipolar, successive-approximation converter with eight modes of oper-
ation. It has selectable 8- or 10-bit resolution. Monotonicity is guaranteed in both
modes.
A bus interface unit handles communication between the ADC and other microcontrol-
ler modules, and supplies IMB timing signals to the ADC. Special operating modes
and test functions are controlled by a module configuration register (ADCMCR) and a
factory test register (ADCTST).
ADC module conversion functions can be grouped into three basic subsystems: an an-
alog front end, a digital control section, and result storage. Figure 8-1 is a functional
block diagram of the ADC module.
In addition to use as multiplexer inputs, the eight analog inputs can be used as a gen-
eral-purpose digital input port (port ADA), provided signals are within logic level spec-
ification. A port data register (PORTADA) is used to access input data.
8.2 External Connections
The ADC uses 12 pins on the MCU package. Eight pins are analog inputs (which can
also be used as digital inputs), two pins are dedicated analog reference connections
(V_RH and V_RL), and two pins are analog supply connections (V_DDA and V_SSA).
M68HC16 Z SERIES
ANALOG-TO-DIGITAL CONVERTER
USER’S MANUAL
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8-1
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