mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 187

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

9.4.7.2
If ADACK is selected as the conversion clock, the ADC continues operation during stop3 mode. For
guaranteed ADC operation, the MCU’s voltage regulator must remain active during stop3 mode. Consult
the module introduction for configuration information for this MCU.
If a conversion is in progress when the MCU enters stop3 mode, it continues until completion. Conversions
can be initiated while the MCU is in stop3 mode by means of the hardware trigger or if continuous
conversions are enabled.
A conversion complete event sets the COCO and generates an ADC interrupt to wake the MCU from stop3
mode if the ADC interrupt is enabled (AIEN = 1).
9.4.8
The ADC module is automatically disabled when the MCU enters stop2 mode. All module registers
contain their reset values following exit from stop2. Therefore, the module must be re-enabled and
re-configured following exit from stop2.
9.5
This section gives an example that provides some basic direction on how to initialize and configure the
ADC module. You can configure the module for 8-, 10-, or 12-bit resolution, single or continuous
conversion, and a polled or interrupt approach, among many other options. Refer to
and
9.5.1
9.5.1.1
Before the ADC module can be used to complete conversions, an initialization procedure must be
performed. A typical sequence is as follows:
Freescale Semiconductor
1. Update the configuration register (ADCCFG) to select the input clock source and the divide ratio
Table 9-9
used to generate the internal clock, ADCK. This register is also used for selecting sample time and
low-power configuration.
Initialization Information
MCU Stop2 Mode Operation
ADC Module Initialization Example
Stop3 Mode With ADACK Enabled
Initialization Sequence
for information used in this example.
The ADC module can wake the system from low-power stop and cause the
MCU to begin consuming run-level currents without generating a system
level interrupt. To prevent this scenario, software should ensure the data
transfer blocking mechanism (discussed in
Conversions) is cleared when entering stop3 and continuing ADC
conversions.
Hexadecimal values designated by a preceding 0x, binary values designated
by a preceding %, and decimal values have no preceding character.
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
NOTE
NOTE
Section 9.4.4.2, “Completing
Analog-to-Digital Converter (S08ADC12V1)
Table
9-7,
Table
9-8,
9-21