MC68HC05B6_13 Datasheet, PDF (101/302 Pages) Freescale Semiconductor, Inc – Microcontrollers

8.2
A/D registers
8.2.1 Port D data register (PORTD)
Port D data (PORTD)
Address bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
State
on reset
$0003 PD7 PD6 PD5 PD4 PD3 PD2 PD1 PD0 Undefined
Port D is an input-only port which routes the eight analog inputs to the A/D converter. When the
A/D converter is disabled, the pins are configured as standard input-only port pins, which can be
read via the port D data register.
Note:
When the A/D function is enabled, pins PD0–PD7 will act as analog inputs. Using a pin
or pins as A/D inputs does not affect the ability to read port D as static inputs; however,
reading port D during an A/D conversion sequence may inject noise on the analog
inputs and result in reduced accuracy of the A/D result.
Performing a digital read of port D with levels other than V_DD or V_SS on the pins will
result in greater power dissipation during the read cycle, and may give unpredictable
results on the corresponding port D pins.
8.2.2 A/D result data register (ADDATA)
8
A/D data (ADDATA)
Address bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
State
on reset
$0008
0000 0000
ADDATA is a read-only register which is used to store the results of A/D conversions. Each result
is loaded into the register from the SAR and the conversion complete flag, COCO, in the ADSTAT
register is set.
MC68HC05B6
Rev. 4.1
ANALOG TO DIGITAL CONVERTER
Freescale
8-3