Enhanced Queued Analog-to-Digital Converter (eQADC)
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor
19-115
c) Read and save EQADC_CFTCRn[TC_CF
n
]
(see
Section 19.3.2.9, “eQADC CFIFO Transfer
Counter Registers 0–5 (EQADC_CFTCRn)
”) for later resuming the scan of the queue. The
TC_CF
n
provides the point of resumption.
d) Since all result data may not have being stored in the appropriate RFIFO at the time MODE
n
is changed to disable, wait for all expected results to be stored in the RFIFO/result queue before
reconfiguring the eDMA to work with the modified result queue. The number of results that
must return can be estimated from the TC_CF
n
value obtained above.
2. Disable the eDMA from responding to the eDMA request generated by EQADC_FISRn[CFFF
n
]
and EQADC_FISRn[RFDF
n
] (see
Section 19.3.2.8, “eQADC FIFO and Interrupt Status Registers
”).
3. Write “0x0000” to the TC_CF
n
field.
4. Load the new configuration and conversion commands into RAM. Configure the eDMA to support
the new command/result queue, but do not configure it yet to respond to eDMA requests from
CFIFO
n
/RFIFO
n
.
5. If necessary, modify the EQADC_IDCRn registers (see
Section 19.3.2.7, “eQADC Interrupt and
eDMA Control Registers 0–5 (EQADC_IDCRn)
”) to suit the modified command queue.
6. Write 1 to EQADC_CFCRn[CFINV
n
] (see
Section 19.3.2.6, “eQADC CFIFO Control Registers
”) to invalidate the entries of CFIFO
n
.
7. Configure the eDMA to respond to eDMA requests generated by CFFF
n
and RFDF
n
.
8. Change MODE
n
to the modified CFIFO operation mode. Write 1 to SSE
n
to trigger CFIFO
n
if
MODE
n
is software trigger.
19.5.5
Command Queue and Result Queue Usage
is an example of command queue and result queue usage. It shows the command queue 0
commands requesting results that are stored in result queue 0 and result queue 1, and command queue 1
commands requesting results that are stored only in result queue 1. Some command messages request data
to be returned from the on-chip ADC/external device, but some only configure them and do not request
returning data. When a command queue contains both write and read commands like command queue 0,
the command queue and result queue entries are not aligned, in
, the result for the second
command of command queue 0 is the first entry of result queue 0. The figure also shows that command
queue and result queue entries can also become unaligned even if all commands in a command queue
request data as command queue 1. Command queue 1 entries became unaligned to result queue 1 entries
because a result requested by the forth command queue 0 command was sent to result queue 1. This
happens because the system can be configured so that several command queues can have results sent to a
single result queue.
Summary of Contents for MPC5566
Page 81: ...Introduction MPC5566 Microcontroller Reference Manual Rev 2 1 24 Freescale Semiconductor...
Page 135: ...Signal Description MPC5566 Microcontroller Reference Manual Rev 2 2 54 Freescale Semiconductor...
Page 189: ...Reset MPC5566 Microcontroller Reference Manual Rev 2 4 20 Freescale Semiconductor...
Page 603: ...Flash Memory MPC5566 Microcontroller Reference Manual Rev 2 13 38 Freescale Semiconductor...
Page 609: ...SRAM MPC5566 Microcontroller Reference Manual Rev 2 14 6 Freescale Semiconductor...
Page 1073: ...MPC5566 Microcontroller Reference Manual Rev 2 22 36 Freescale Semiconductor...
Page 1185: ...Nexus MPC5566 Microcontroller Reference Manual Rev 2 25 92 Freescale Semiconductor...
