MC68HC908LD64 Datasheet, PDF (179/362 Pages) Freescale Semiconductor, Inc – Microcontrollers

Analog-to-Digital Converter (ADC)
Functional Description
13.4 Functional Description
Six ADC channels are available for sampling external sources at pins
PTC5–PTC0. An analog multiplexer allows the single ADC converter to
select one of the six 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 DDRC
WRITE DDRC
WRITE PTC
RESET
DDRCx
PTCx
DISABLE
PTCx/ADCx
READ PTC
ADC DATA REGISTER
DISABLE
ADC CHANNEL x
CONVERSION
INTERRUPT COMPLETE
LOGIC
AIEN COCO
BUS CLOCK
ADC VOLTAGE IN
ADCVIN
CHANNEL
ADC
SELECT
(1 OF 6 CHANNELS)
ADC CLOCK
CLOCK
GENERATOR
ADIV[2:0]
Figure 13-2. ADC Block Diagram
MC68HC908LD64 — Rev. 3.0
Freescale Semiconductor
Analog-to-Digital Converter (ADC)
ADCH[4:0]
Data Sheet
179