Enhanced Queued Analog-to-Digital Converter (eQADC)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
31-78
Freescale Semiconductor
Preliminary
Figure 31-47. Command Queue/CFIFO Interface
31.5.2.2
Receive Queue/RFIFO Transfers
In transfers involving receive queues and RFIFOs, the eDMA controller moves data from a single source
to a queue destination as shown in
. The location of the data to be moved is indicated by the
source address, and the final destination for that data, by the destination address. For every eDMA request
issued by the EQADC, the eDMA controller has to be configured to transfer a single result (16-bit data),
pointed to by the source address, from the RFIFO pop register to the receive queue, pointed to by the
destination address. After the service of an eDMA request is completed, the destination address has to be
updated to point to the location where the next 16-bit result will be stored. The source address remains
unchanged. When the last expected result is written to the receive queue, one of the following actions is
recommended. Refer to
Chapter 12, “Enhanced Direct Memory Access (eDMA)
” for details about how
this functionality is supported.
•
The corresponding eDMA channel should be disabled.
•
The destination address should be updated pointed to the next location where new coming results
are stored, which can be the first entry of the current receive queue (cyclic queue), or the beginning
of a new receive queue.
Figure 31-48. Receive Queue/RFIFO Interface
31.5.3
Sending Immediate Command Setup Example
In the eQADC, there is no immediate command register for sending a command immediately after writing
to that register. However, a CFIFO can be configured to perform the same function as an immediate
Command 1
Command 2
Command 3
•
Command n-1
Command n
One command transfer
per DMA request
CFPRx
Source Address
Destination Address
CFIFO Push Register
•
•
••
•
eDMA_TCDn
Result 1
Result 2
Result 3
•
Result n-1
Result n
One result transfer
per DMA request
RFPRx
Source Address
Destination Address
RFIFO Pop Register
•
•
••
•
