
Enhanced Queued Analog-to-Digital Converter (eQADC)
MPC5566 Microcontroller Reference Manual, Rev. 2
19-78
Freescale Semiconductor
The NCF flag is used to indicate command sequence non-coherency. When the NCF
n
flag is asserted, it
indicates that the command sequence being transferred through CFIFO
n
became non-coherent. The NCF
flag only becomes asserted for CFIFOs in a TRIGGERED state.
A command sequence is non-coherent when, after transferring the first command of a sequence from a
CFIFO to a buffer, it cannot successively send all the other commands of the sequence before any of the
following conditions are true:
•
The CFIFO through which commands are being transferred is pre-empted by a higher priority
CFIFO which sends commands to the same ADC. The NCF flag becomes asserted immediately
after the first command transfer from the pre-empting CFIFO, that is the higher priority CFIFO, to
the ADC in use is completed. Refer to
•
The external command buffer in use becomes empty. (Only the fullness of external buffers is
monitored because the fill rate for internal ADC buffers is many times faster than the drain rate,
and each has a dedicated priority engine.)
This case happens when different CFIFOs attempt to use
different external command buffers and the higher priority CFIFO bars the lower priority one from
sending new commands to its buffer—see
. An external command buffer is
considered empty when the corresponding BUSY field in the last result message received from
external device is encoded as “Send available commands - buffer is empty”. Refer to
“Result Message Format for External Device Operation
.” The NCF flag becomes asserted
immediately after the eQADC detects that the external buffer in use becomes empty.
NOTE
After the transfer of a command sequence to an external command buffer
starts, the eQADC ignores, for non-coherency detection purposes, the
BUSY fields captured at the end of the first serial transmission. Thereafter,
all BUSY fields captured at the end of consecutive serial transmissions are
used to check the fullness of that external command buffer. This is done
because the eQADC only updates its external ADC command buffer status
record when it receives a serial message, resulting that the record kept by
the eQADC is always outdated by, at least, the length of one serial
transmission. This prevents a CFIFO from immediately becoming
non-coherent when it starts transferring commands to an empty external
command buffer. Refer to
Figure 19-42. External Command Buffer Status Detection at Command Sequence Transfer Start
SDS
Null Message
Serial Data
Transmitted
1) The CFIFO starts sending commands to an external command buffer when triggered.
2) Execution of a command on the external device takes longer than the time to
Assumptions:
complete two serial transmissions.
Command 3
Command 2
Command 1
(a)
(b)
(c)
Transfer of Command
Sequence Starts
External Buffer Status Starts
to be Monitored Here
Содержание MPC5566
Страница 12: ...MPC5566 Microcontroller Reference Manual Devices Supported MPC5566 MPC5566 RM Rev 2 0 23 Apr 2008...
Страница 81: ...Introduction MPC5566 Microcontroller Reference Manual Rev 2 1 24 Freescale Semiconductor...
Страница 135: ...Signal Description MPC5566 Microcontroller Reference Manual Rev 2 2 54 Freescale Semiconductor...
Страница 189: ...Reset MPC5566 Microcontroller Reference Manual Rev 2 4 20 Freescale Semiconductor...
Страница 331: ...System Integration Unit SIU MPC5566 Microcontroller Reference Manual Rev 2 6 128 Freescale Semiconductor...
Страница 343: ...Crossbar Switch XBAR MPC5566 Microcontroller Reference Manual Rev 2 7 12 Freescale Semiconductor...
Страница 361: ...Error Correction Status Module ECSM MPC5566 Microcontroller Reference Manual Rev 2 8 18 Freescale Semiconductor...
Страница 455: ...Interrupt Controller INTC MPC5566 Microcontroller Reference Manual Rev 2 10 42 Freescale Semiconductor...
Страница 603: ...Flash Memory MPC5566 Microcontroller Reference Manual Rev 2 13 38 Freescale Semiconductor...
Страница 609: ...SRAM MPC5566 Microcontroller Reference Manual Rev 2 14 6 Freescale Semiconductor...
Страница 679: ...Boot Assist Module BAM MPC5566 Microcontroller Reference Manual Rev 2 16 20 Freescale Semiconductor...
Страница 997: ...Deserial Serial Peripheral Interface DSPI MPC5566 Microcontroller Reference Manual Rev 2 20 72 Freescale Semiconductor...
Страница 1037: ...Enhanced Serial Communication Interface eSCI MPC5566 Microcontroller Reference Manual Rev 2 21 40 Freescale Semiconductor...
Страница 1073: ...MPC5566 Microcontroller Reference Manual Rev 2 22 36 Freescale Semiconductor...
Страница 1081: ...Voltage Regulator Controller VRC and POR Module MPC5566 Microcontroller Reference Manual Rev 2 23 8 Freescale Semiconductor...
Страница 1093: ...IEEE 1149 1 Test Access Port Controller JTAGC MPC5566 Microcontroller Reference Manual Rev 2 24 12 Freescale Semiconductor...
Страница 1185: ...Nexus MPC5566 Microcontroller Reference Manual Rev 2 25 92 Freescale Semiconductor...
Страница 1267: ...MPC5566 Reference Manual Revision History MPC5566 Microcontroller Reference Manual Rev 2 Freescale Semiconductor C 10...
Страница 1268: ...MPC5566 Reference Manual Revision History MPC5566 Microcontroller Reference Manual Rev 2 Freescale Semiconductor C 11...