PXR40RM Datasheet, PDF (1106/1434 Pages) Freescale Semiconductor, Inc – PXR40 Microcontroller

Enhanced Queued Analog-to-Digital Converter (EQADC)
27.8.5 CQueue and RQueues Usage
Figure 27-76 is an example of CQueue and RQueue usage. It shows the CQueue0 commands requesting
results that will be stored in RQueue0 and RQueue1, and CQueue1 commands requesting results that will
be stored only in RQueue1. Some Command Messages request data to be returned from the on-chip ADC,
but some only configure them and do not request returning data. When a CQueue contains both write and
read commands like CQueue0, the CQueue and RQueue entries will not be aligned; as shown in
Figure 27-76, the result for the second command of CQueue0 is the first entry of RQueue0. The figure also
shows that CQueue and RQueue entries can also become unaligned even if all commands in a CQueue
request data as CQueue1. CQueue1 entries became unaligned to RQueue1 entries because a result
requested by the forth CQueue0 command was sent to RQueue1. This happens because the system can be
configured so that several CQueues can have its results sent to a single RQueue.
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PXR40 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor