Enhanced Queued Analog-to-Digital Converter (eQADC)
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 19-25
12
RFOFn
RFIFO overflow flag n. Indicates an overflow event on RFIFOn. RFOFn is set when RFIFOn is already full, and a
new data is received from the on-chip ADCs or from the external device. The RFIFOn does not overwrite older data
in the RFIFO, and the new data is ignored. When RFOIEn (see Section 19.3.2.7, “eQADC Interrupt and eDMA
Control Registers 0–5 (EQADC_IDCRn)”) and RFOFn are both asserted, the eQADC generates an interrupt
request.
Apart from generating an independent interrupt request for an RFIFOn overflow event, the eQADC also provides a
combined interrupt at which the result FIFO overflow interrupt, the command FIFO underflow interrupt, and the
command FIFO trigger overrun interrupt requests of all CFIFOs are ORed. When RFOIEn, CFUIEn, and TORIEn
are all asserted, this combined interrupt request is asserted whenever one of the following 18 flags becomes
asserted: RFOFn, CFUFn, and TORFn (assuming that all interrupts are enabled). Refer to Section 19.4.7, “eQADC
eDMA/Interrupt Request,” for details.
Write 1 to clear RFOFn. Writing a 0 has no effect.
0 No RFIFO overflow event occurred.
1 An RFIFO overflow event occurred.
13 Reserved.
14
RFDFn
RFIFO drain flag n. Indicates if RFIFOn has valid entries that can be drained or not. RFDFn is set when the RFIFOn
has at least one valid entry in it. When RFDEn (see Section 19.3.2.7, “eQADC Interrupt and eDMA Control Registers
0–5 (EQADC_IDCRn)”) and RFDFn are both asserted, an interrupt or an eDMA request is generated depending on
the status of the RFDSn bit. When RFDSn is negated (interrupt requests selected), software clears RFDFn by writing
a 1 to it. Writing a 0 has no effect. When RFDSn is asserted (eDMA requests selected), RFDFn is automatically
cleared by the eQADC when the RFIFO becomes empty.
0 RFIFOn is empty.
1 RFIFOn has at least one valid entry.
Note: In the interrupt service routine, RFDF must be cleared only after the RFIFOn pop register is read.
Note: RFDFn should not be cleared when RFDSn is asserted (eDMA requests selected).
15 Reserved.
16–19
CFCTRn
[0:3]
CFIFOn entry counter. Indicates the number of commands stored in the CFIFOn. When the eQADC completes
transferring a piece of new data from the CFIFOn, it decrements CFCTRn by 1. Writing a word or any bytes to the
corresponding CFIFO Push Register (see Section 19.3.2.4, “eQADC CFIFO Push Registers 0–5
(EQADC_CFPRn)”) increments CFCTRn by 1. Writing any value to CFCTRn has no effect.
20–23
TNX
TPTRn
[0:3]
CFIFOn transfer next pointer. Indicates the index of the next entry to be removed from CFIFOn when it completes a
transfer. When TNXTPTRn is 0, it points to the entry with the smallest memory-mapped address inside CFIFOn.
TNXTPTRn is only updated when a command transfer is completed. If the maximum index number (CFIFO depth
minus 1) is reached, TNXTPTRn is wrapped to 0, else, it is incremented by 1. For details refer to Section 19.4.3.1,
“CFIFO Basic Functionality.” Writing any value to TNXTPTRn has no effect.
24–27
RFCTRn
[0:3]
RFIFOn entry counter. Indicates the number of data items stored in the RFIFOn. When the eQADC stores a piece
of new data into RFIFOn, it increments RFCTRn by 1. Reading the whole word, halfword or any bytes of the
corresponding Result FIFO pop register (see Section 19.3.2.5, “eQADC Result FIFO Pop Registers 0–5
(EQADC_RFPRn)”) decrements RFCTRn by 1. Writing any value to RFCTRn itself has no effect.
28–31
POPNX
TPTRn
[0:3]
RFIFOn pop next pointer. Indicates the index of the entry that is returned when EQADC_RFPRn is read. When
POPNXTPTRn is 0, it points to the entry with the smallest memory-mapped address inside RFIFOn. POPNXTPTRn
is updated when EQADC_RFPRn is read. If the maximum index number (RFIFO depth minus 1) is reached,
POPNXTPTRn
is wrapped to 0, else, it is incremented by 1. For details refer to Section 19.4.4.1, “RFIFO Basic
Functionality.” Writing any value to POPNXTPTRn has no effect.
Table 19-12. EQADC_FISRn Field Descriptions (continued)
Field Description
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