MC68HC908AB32 Datasheet, PDF (231/392 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Analog-to-Digital Converter (ADC)
14.4 Functional Description
The ADC provides eight pins for sampling external sources at pins
PTB7/ATD7–PTB0/ATD0. An analog multiplexer allows the single ADC
converter to select one of eight ADC channels as ADC voltage in
(V_ADIN). V_ADIN is converted by the successive approximation
register-based analog-to-digital converter. When the conversion is
completed, ADC places the result in the ADC data register and sets a
flag or generates an interrupt. (See Figure 14-2.)
INTERNAL
DATA BUS
READ DDRBx
WRITE DDRBx
RESET
WRITE PTBx
READ PTBx
DDRBx
PTBx
DISABLE
PTBx
ADC CHANNEL x
DISABLE
ADC DATA REGISTER
ADC I/P CHANNELS
CONVERSION
INTERRUPT ^COMPLETE
LOGIC
ADC
ADC
VOLTAGE IN
(V_ADIN)
CHANNEL
SELECT
ADCH[4:0]
AIEN COCO
CGMXCLK
BUS CLOCK
ADC CLOCK
CLOCK
GENERATOR
ADIV[2:0] ADICLK
Figure 14-2. ADC Block Diagram
MC68HC908AB32 — Rev. 1.1
Freescale Semiconductor
Analog-to-Digital Converter (ADC)
Technical Data
231