MPC563XM Reference Manual, Rev. 1
Freescale Semiconductor
1103
Preliminary—Subject to Change Without Notice
Figure 24-94. RQueue/RFIFO Interface
24.7.3
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 register. The following steps illustrate how to configure CFIFO5 as an immediate command
CFIFO. The results will be returned to RFIFO5.
1.
Configure the
Section 24.5.2.8, “EQADC Interrupt and DMA Control Registers (EQADC_IDCR)
a.
Clear CFIFO Fill Enable5 (CFFE5 = 0) in EQADC_IDCR2.
b.
Clear CFIFO Underflow Interrupt Enable5 (CFUIE5 = 0) in EQADC_IDCR2.
c.
Clear RFDS5 to configure the EQADC to generate interrupt requests to pop result data from
RFIF05.
d.
Set RFIFO Drain Enable5 (RFDE5 = 1) in EQADC_IDCR2.
2.
Configure the
Section 24.5.2.7, “EQADC CFIFO Control Registers (EQADC_CFCR)
.
a.
Write “1” to CFINV5 in EQADC_FCR2. This will invalidate the contents of CFIFO5.
b.
Set MODE5 to Continuous-Scan Software Trigger mode in EQADC_CFCR2.
3.
To transfer a command, write it to EQADC CFIFO Push Register 5 (EQADC_CFPR5) with
Message Tag = 0b0101. Refer to
Section 24.5.2.5, “EQADC CFIFO Push Registers
4.
Up to four commands can be queued in CFIFO5. Check the CFCTR5 status in EQADC_FISR5
before pushing another command to avoid overflowing the CFIFO. Refer to
“EQADC FIFO and Interrupt Status Registers (EQADC_FISR)
.
5.
When the EQADC receives a conversion result for RFIFO5, it generates an interrupt request.
RFIFO Pop Register 5 (EQADC_RFPR5) can be popped to read the result. Refer to
Result 1
Result 2
Result 3
.....
Result n-1
Result n
RFPRx
RQueue in
system memory
RFIFO
Pop Register
One result transfer per DMA
request
Source Address
Destination Address