PXS20RM Datasheet, PDF (197/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Analog-to-Digital Converter (ADC)
of channel B starts followed by conversion of the channels D-E. This sequence repeats itself till the
MCR[NSTART] bit is cleared by software.
At the end of each conversion an End Of Conversion interrupt is issued (if enabled by the corresponding
mask bit) and at the end of the conversion sequence an End Of Chain interrupt is issued (if enabled by the
corresponding mask bit).
9.4.2.4 Injected channel conversion
A conversion chain can be injected into the ongoing normal conversion by configuring the Injected
Conversion Mask Registers (JCMR). As normal conversion, each channel can be individually selected.
This injected conversion can only occur in One Shot mode and interrupts the normal conversion. When an
injected conversion is inserted, ongoing channel conversion is aborted and the injected channel request is
processed. After the last channel in the injected chain is converted, normal conversion resumes from the
channel at which the normal conversion was stopped as shown in Figure 9-45.
Sample B Evaluate B Sample C Evaluate C Sample D Evaluate D Sample E Evaluate E
Sample C Abort C
Injected conversion of channels I and J
Sample I Evaluate I Sample J Evaluate J Sample C Evaluate C
The ongoing channel conversion is interrupted and the injected
conversion chain is processed first, after the injected chain is converted
the normal chain conversion resumes from the channel at which normal
conversion was aborted.
Normal conversion resumes from
the last aborted channel.
Figure 9-45. Injected sample/conversion sequence
The MSR[JSTART] status bit is automatically set when the injected conversion starts. At the same time
the MCR[JSTART] bit is cleared, allowing the software to program a new start of conversion. In that case
the new requested conversion starts after the running injected conversion is completed.
At the end of each injected conversion, an End Of Injected Conversion (JEOC) interrupt is issued (if
enabled by the corresponding mask bit) and at the end of the sequence an End Of Injected Chain (JECH)
interrupt is issued (if enabled by the corresponding mask bit).
If the content of all the injected conversion mask registers is zero (that is, no channel is selected) the
interrupt JECH is immediately issued after the start of conversion.
Once started, injected chain conversion cannot be interrupted by any other conversion type. It can,
however, be aborted; see Section 9.4.2.5, Abort conversion.
9.4.2.5 Abort conversion
Two different abort functions are provided.
• The user can abort the ongoing conversion by setting the MCR[ABORT] bit. The current
conversion is aborted and the conversion of the next channel of the chain is immediately started
Freescale Semiconductor
PXS20 Microcontroller Reference Manual, Rev. 1
9-39