Freescale Semiconductor MPC5565, Справочное руководство

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Enhanced Queued Analog-to-Digital Converter (eQADC)
MPC5565 Microcontroller Reference Manual, Rev. 1.0
18-26 Freescale Semiconductor
12
RFOF n
RFIFO overflow flag n . Indicates an overflow event on RFIFO n . RFOF n is set when RFIFO n is already full, and a
new data is received from the on-chip ADCs or from the external device. The RFIFO n does not overwrite older data
in the RFIFO, and the new data is ignored. When RFOIE n (see Section 18.3.2.7, “eQADC Interrupt and eDMA
Control Registers 0–5 (EQADC_IDCRn) ”) and RFOF n are both asserted, the eQADC generates an interrupt
request.
Apart from generating an independent interrupt request for an RFIFO
n 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 RFOIE
n , CFUIE n , and TORIE n
are all asserted, this combined interrupt request is asserted whenever one of the following 18 flags becomes
asserted: RFOF
n , CFUF n , and TORF n (assuming that all interrupts are enabled). Refer to Section 18.4.7, “eQADC
eDMA/Interrupt Request ,” for details.
Write 1 to clear RFOF n . Writing a 0 has no effect.
0 No RFIFO overflow event occurred.
1 An RFIFO overflow event occurred.
13 Reserved.
14
RFDF n
RFIFO drain flag n . Indicates if RFIFO n has valid entries that can be drained or not. RFDF n is set when the RFIFO n
has at least one valid entry in it. When RFDE n (see Section 18.3.2.7, “eQADC Interrupt and eDMA Control Registers
0–5 (EQADC_IDCRn) ”) and RFDF n are both asserted, an interrupt or an eDMA request is generated depending on
the status of the RFDS n bit. When RFDS n is negated (interrupt requests selected), software clears RFDF n by writing
a 1 to it. Writing a 0 has no effect. When RFDS n is asserted (eDMA requests selected), RFDF n is automatically
cleared by the eQADC when the RFIFO becomes empty.
0 RFIFO
n is empty.
1 RFIFO n has at least one valid entry.
Note: In the interrupt service routine, RFDF must be cleared only after the RFIFO n pop register is read.
Note: RFDF n should not be cleared when RFDS n is asserted (eDMA requests selected).
15 Reserved.
16–19
CFCTR n
[0:3]
CFIFO n entry counter. Indicates the number of commands stored in the CFIFO n . When the eQADC completes
transferring a piece of new data from the CFIFO n , it decrements CFCTR n by 1. Writing a word or any bytes to the
corresponding CFIFO Push Register (see Section 18.3.2.4, “eQADC CFIFO Push Registers 0–5
(EQADC_CFPRn) ”) increments CFCTR n by 1. Writing any value to CFCTR n has no effect.
20–23
TNX
TPTR n
[0:3]
CFIFO n transfer next pointer. Indicates the index of the next entry to be removed from CFIFO n when it completes a
transfer. When TNXTPTR n is 0, it points to the entry with the smallest memory-mapped address inside CFIFO n .
TNXTPTR n is only updated when a command transfer is completed. If the maximum index number (CFIFO depth
minus 1) is reached, TNXTPTR n is wrapped to 0, else, it is incremented by 1. For details refer to Section 18.4.3.1,
“CFIFO Basic Functionality .” Writing any value to TNXTPTR n has no effect.
24–27
RFCTR n
[0:3]
RFIFO n entry counter. Indicates the number of data items stored in the RFIFO n . When the eQADC stores a piece
of new data into RFIFO n, it increments RFCTR n by 1. Reading the whole word, halfword or any bytes of the
corresponding Result FIFO pop register (see Section 18.3.2.5, “eQADC Result FIFO Pop Registers 0–5
(EQADC_RFPRn) ”) decrements RFCTR n by 1. Writing any value to RFCTR n itself has no effect.
28–31
POPNX
TPTR n
[0:3]
RFIFO n pop next pointer. Indicates the index of the entry that is returned when EQADC_RFPR n is read. When
POPNXTPTR n is 0, it points to the entry with the smallest memory-mapped address inside RFIFO n . POPNXTPTR n
is updated when EQADC_RFPR n is read. If the maximum index number (RFIFO depth minus 1) is reached,
POPNXTPTR n is wrapped to 0, else, it is incremented by 1. For details refer to Section 18.4.4.1, “RFIFO Basic
Functionality .” Writing any value to POPNXTPTR n has no effect.
Table 18-12. EQADC_FISR n Field Descriptions (continued)
Field Description