MC68HC908JG16 Datasheet, PDF (247/324 Pages) Motorola, Inc – Microcontrollers

Analog-to-Digital Converter (ADC)
Functional Description
13.4 Functional Description
Eight ADC channels are available for sampling external sources at pins
PTA7–PTA0. An analog multiplexer allows the single ADC converter to
select one of the eight ADC channels as ADC voltage input (ADCVIN).
ADCVIN is converted by the successive approximation register-based
counters. The ADC resolution is eight bits. When the conversion is
completed, ADC puts the result in the ADC data register and sets a flag
or generates an interrupt. Figure 13-2 shows a block diagram of the
ADC.
INTERNAL
DATA BUS
READ DDRA
WRITE DDRA
WRITE PTA
RESET
DDRAx
PTAx
DISABLE
PTAx/KBAx/ADx
READ PTA
ADC DATA REGISTER
DISABLE
ADC CHANNEL x
CONVERSION
INTERRUPT COMPLETE
LOGIC
AIEN COCO
BUS CLOCK
ADC
ADC VOLTAGE IN
ADCVIN
CHANNEL
SELECT
(1 OF 8 CHANNELS)
ADC CLOCK
CLOCK
GENERATOR
ADCH[4:0]
ADIV[2:0]
Figure 13-2. ADC Block Diagram
MC68HC908JG16 — Rev. 1.1
Freescale Semiconductor
Analog-to-Digital Converter (ADC)
Technical Data
247