mc9s08gt16a Freescale Semiconductor, Inc, mc9s08gt16a Datasheet - Page 225

• Manufacturer Part Number: mc9s08gt16a
• Description: Hcs08 Microcontrollers 8-bit Microcontroller Family
• Manufacturer: Freescale Semiconductor, Inc

14.2.1
The channel pins are used as the analog input pins of the ATD. Each pin is connected to an analog switch
which serves as the signal gate into the sample submodule.
14.2.2
These pins serve as the source for the high and low reference potentials for the converter. Separation from
the power supply pins accommodates the filtering necessary to achieve the accuracy of which the system
is capable.
14.2.3
These two pins are used to supply power and ground to the analog section of the ATD. Dedicated power
is required to isolate the sensitive analog circuitry from the normal levels of noise present on digital power
supplies.
14.3
The ATD has seven registers that control ATD functions.
Refer to the direct-page register summary in the memory chapter of this data sheet for the absolute address
assignments for all ATD registers. This section refers to registers and control bits only by their names. A
Freescale-provided equate or header file is used to translate these names into the appropriate absolute
addresses.
14.3.1
Writes to the ATD control register will abort the current conversion, but will not start a new conversion.
Freescale Semiconductor
Register Definition
ADP7–ADP0 — Channel Input Pins
V
V
ATD Control (ATDC)
REFH
DDAD
V
must be at the same potential.
DDAD1
, V
, V
REFL
SSAD
and V
AD7–AD0
DD
— ATD Reference Pins
V
— ATD Supply Pins
V
V
Name
V
DDAD
REFH
SSAD
REFL
must be at the same potential. Likewise, V
MC9S08GT16A/GT8A Data Sheet, Rev. 1
Table 14-1. Signal Properties
High reference voltage for ATD converter
Low reference voltage for ATD converter
ATD ground supply voltage
ATD power supply voltage
NOTE
Channel input pins
Function
Analog-to-Digital Converter (S08ATDV3)
SSAD1
and V
SS
225