MPC5604B/C Microcontroller Reference Manual, Rev. 8
Freescale Semiconductor 595
Example 25-1. One Shot Mode (MODE = 0)
Channels A-B-C-D-E-F-G-H are present in the device where channels B-D-E are to be converted
in the One Shot Mode. MODE = 0 is set for One Shot mode. Conversion starts from the channel B
followed by conversion of channels D-E. At the end of conversion of channel E the scanning of
channels stops.
The NSTART status bit in the MSR is automatically set when the Normal conversion starts. At the same
time the MCR[NSTART] bit is reset, allowing the software to program a new start of conversion. In that
case the new requested conversion starts after the running conversion is completed.
In Scan Mode (MODE = 1), a sequential conversion of N channels specified in the NCMR registers is
continuously performed. As in the previous case, at the end of each conversion the digital result of the
conversion is stored into the corresponding data register.
The MSR[NSTART] status bit is automatically set when the Normal conversion starts. Unlike One Shot
Mode, the MCR[NSTART] bit is not reset. It can be reset by software when the user needs to stop scan
mode. In that case, the ADC completes the current scan conversion and, after the last conversion, also
resets the MSR[NSTART] bit.
Example 25-2. Scan Mode (MODE = 1)
Channels A-B-C-D-E-F-G-H are present in the device where channels B-D-E are to be converted
in the Scan Mode. MODE = 1 is set for Scan Mode. Conversion starts from the channel B followed
by conversion of the channels D-E. At the end of conversion of channel E the scanning 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.
If the conversion is started by an external trigger and EDGLEV is ‘0’, the MCR[NSTART] bit is not set.
As a consequence, once started the only way to stop scan mode conversion is to set the MODE bit to ‘0’.
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 in the IMR register).
25.3.1.4 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 (which can only occur in One Shot mode) interrupts the normal conversion(which
can be in One Shot or Scan mode). When an injected conversion is inserted, ongoing normal 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
aborted as shown in Figure 25-3.
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