MPC563XM Reference Manual, Rev. 1
Freescale Semiconductor
1105
Preliminary—Subject to Change Without Notice
24.7.5
CQueue and RQueues Usage
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/external device, 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
, 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.