mc9s12c32mpb16 Freescale Semiconductor, Inc, mc9s12c32mpb16 Datasheet - Page 247

• Manufacturer Part Number: mc9s12c32mpb16
• Description: Hcs12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

8.4.2.2
The 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. Alternatively they can be configured as
digital I/O signals with the port I/O data being held in PORTAD.
The analog/digital multiplex operation is performed in the pads. The pad is always connected to the analog
inputs of the ATD10B8C. The 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.
8.4.2.3
The ATD10B8C can be configured for lower MCU power consumption in three different ways:
8.5
8.5.1
The following describes a typical setup procedure for starting A/D conversions. It is highly recommended
to follow this procedure to avoid common mistakes.
Each step of the procedure will have a general remark and a typical example
8.5.1.1
Power up the ATD and concurrently define other settings in ATDCTL2
Example: Write to ATDCTL2: ADPU=1 -> powers up the ATD, ASCIE=1 enable interrupt on finish of a
conversion sequence.
8.5.1.2
Wait for the ATD Recovery Time
Example: Use the CPU in a branch loop to wait for a defined number of bus clocks.
Freescale Semiconductor
1. Stop Mode: This halts A/D conversion. Exit from Stop mode will resume A/D conversion, But due
2. Wait Mode with AWAI = 1: This halts A/D conversion. Exit from Wait mode will resume A/D
3. Writing ADPU = 0 (Note that all ATD registers remain accessible.): This aborts any A/D
to the recovery time the result of this conversion should be ignored.
conversion, but due to the recovery time the result of this conversion should be ignored.
conversion in progress.
Initialization/Application Information
Setting up and starting an A/D conversion
General-Purpose Digital Port Operation
Low-Power Modes
Step 1
Step 2
The reset value for the ADPU bit is zero. Therefore, when this module is
reset, it is reset into the power down state.
t
REC
MC9S12C-Family / MC9S12GC-Family
before you proceed with Step 3.
Rev 01.23
NOTE
Chapter 8 Analog-to-Digital Converter (ATD10B8C) Block Description
247