Freescale Semiconductor MPC5553 - Page 838

MPC5553/MPC5554 Microcontroller Reference Manual, Rev. 5
Freescale Semiconductor 19-83
hardware implementation has only four entries. In this example, RFIFOn with 16 entries is shown in
sequence after popping or receiving entries.
Figure 19-47. RFIFO Entry Pointer Example
19.4.4.2 Distributing Result Data into RFIFOs
Data to be moved into the RFIFOs can come from three sources: from ADC0, from ADC1, or from the
external device. All result data comes with a MESSAGE_TAG field defining what should be done with
the received data. The FIFO control unit decodes the MESSAGE_TAG field and:
• Stores the 16-bit data into the appropriate RFIFO if the MESSAGE_TAG indicates a valid RFIFO
number or
First In
Pop
Next
Data
Pointer
Last In
Receive
Next
Data
Pointer
RFIFOn
Pop
Next
Data
Pointer
Receive
Next
Data
Pointer
RFIFOn
First In
Pop
Next
Data
Pointer
Last In
Receive
Next
Data
Pointer
RFIFOn
After Reset or
Invalidation
Some Entries Received
but None Popped
No Entries Received
but Some Popped
First In
Pop
Next
Data
Pointer
Receive
Next
Data
Pointer
RFIFOn
Pop
Next
Data
Pointer
Receive
Next
Data
Pointer
RFIFOn
First In
Pop
Next
Data
Pointer
Last In
Receive
Next
Data
Pointer
RFIFOn
No Entries Received
but Some Popped
Some Entries Received
and Some Popped
Entries Received Until
Full and None Popped
First In
Last In Last In
Valid Entry
Empty Entry
NOTE:
n = 0, 1, 2, 3, 4, 5