MC68HC908MR8 Datasheet, PDF (313/372 Pages) Motorola, Inc – Microcontrollers

INTERNAL
DATA BUS
READ PTA
ADC DATA REGISTERS
Analog-to-Digital Converter (ADC)
Functional Description
PTAx
ADC CHANNEL X
DISABLE
CONVERSION
ADC
INTERRUPT
COMPLETE
ADC
INTERRUPT
LOGIC
ADC VOLTAGE IN
ADVIN
CHANNEL
SELECT
ADCH6:ADCH0
AIEN
ADC CLOCK
CGMXCLK
f_OP
CLOCK
GENERATOR
ADIV[2:0] ADICLK
Figure 18-1. ADC Block Diagram
18.4.1 ADC Port I/O Pins
PTA6/ATD6:PTA0/ATD6 are general-purpose input/output (I/O) pins
that are shared with the ADC channels.
The channel select bits define which ADC channel/port pin will be used
as the input signal. The ADC overrides the port logic when that port is
selected by the ADC multiplexer. The remaining ADC channels/port pins
are controlled by the port logic and can be used as general-purpose
input/output (I/O) pins. Writes to the port register or data direction
register (DDR) will not have any effect on the port pin that is selected by
the ADC. Read of a port pin which is in use by the ADC will return a
logic 0.
MC68HC908MR8 — Rev 4.1
Freescale Semiconductor
Analog-to-Digital Converter (ADC)
Technical Data
313