MC9S12NE64_06 Datasheet, PDF (228/554 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 7 Analog-to-Digital Converter (ATD10B8CV3)
7.4.2.2 General Purpose Digital Input Port Operation
The input channel pins can be multiplexed between analog and digital data. As analog inputs, they are
multiplexed and sampled to supply signals to the A/D converter. As digital inputs, they supply external
input data that can be accessed through the digital port register PORTAD (input-only).
The analog/digital multiplex operation is performed in the input pads. The input pad is always connected
to the analog inputs of the ATD. The input pad signal is buffered to the digital port registers. This buffer
can be turned on or off with the ATDDIEN register. This is important so that the buffer does not draw
excess current when analog potentials are presented at its input.
7.4.2.3 Low Power Modes
The ATD can be configured for lower MCU power consumption in 3 different ways:
1. Stop mode: This halts A/D conversion. Exit from stop mode will resume A/D conversion, but due
to the recovery time the result of this conversion should be ignored.
2. Wait mode with AWAI = 1: This halts A/D conversion. Exit from wait mode will resume A/D
conversion, but due to the recovery time the result of this conversion should be ignored.
3. Writing ADPU = 0 (Note that all ATD registers remain accessible.): This aborts any A/D
conversion in progress.
Note that the reset value for the ADPU bit is zero. Therefore, when this module is reset, it is reset into the
power down state.
7.5 Resets
At reset the ATD is in a power down state. The reset state of each individual bit is listed within the Register
Description section (see Section 7.3, “Memory Map and Register Definition”), which details the registers
and their bit-field.
7.6 Interrupts
The interrupt requested by the ATD is listed in Table 7-24. Refer to the device overview chapter for related
vector address and priority.
Table 7-24. ATD Interrupt Vectors
Interrupt Source
Sequence complete
interrupt
CCR
Mask
I bit
Local Enable
ASCIE in ATDCTL2
See register descriptions for further details.
MC9S12NE64 Data Sheet, Rev. 1.1
228
Freescale Semiconductor