NXP Semiconductors MPC5566 - Trigger Overrun Status

Enhanced Queued Analog-to-Digital Converter (eQADC)
MPC5566 Microcontroller Reference Manual, Rev. 2
19-76 Freescale Semiconductor
19.4.3.6.4 Trigger Overrun Status
When a CFIFO is configured for edge or level trigger mode and is in a TRIGGERED state, an additional
trigger event for the same CFIFO causes a trigger overrun:
1. The trigger overrun bit for the CFIFO is set (EQADC_FISRn[TORFn] = 1)
2. The EQADC_CFCRn[TORIE] and EQADC_FISRn[TORF] assert
3. The eQADC generates a trigger overrun interrupt request.
Refer to the following sections for more information:
Section 19.3.2.8, “eQADC FIFO and Interrupt Status Registers 0–5 (EQADC_FISRn)”
Section 19.3.2.6, “eQADC CFIFO Control Registers 0–5 (EQADC_CFCRn)”
For CFIFOs configured for level trigger mode, a trigger overrun event is detected only when the gate
closes and reopens during a single serial command transmission as shown in Figure 19-40.
Figure 19-40. Trigger Overrun on Level Trigger Mode CFIFOs
NOTE
The trigger overrun flag is not set for CFIFOs configured for software
trigger mode.
19.4.3.6.5 Command Sequence Non-Coherency Detection
The eQADC provides a mechanism to indicate if a command sequence has been completely executed
without interruptions. A command sequence is defined as a group of consecutive commands bound for the
same ADC and it is expected to be executed without interruptions. A command sequence is coherent if its
commands are executed in order without interruptions. Because commands are stored in the ADC’s
command buffers before being executed in the eQADC, a command sequence is coherent if, while it is
transferring commands to an on-chip ADC command buffer, the buffer is only fed with commands from
that sequence without ever becoming empty.
A command sequence starts when:
• A CFIFO in TRIGGERED state transfers its first command to an on-chip ADC.
Command transmission
through eQADC SSI
CFIFO status
TORF
Command 1 Null message Command 2
Triggered WFT Triggered Triggered
WFT
Low active
Level trigger
If gate closes during a command transmission, it is only
recognized when the transmission ends.
1) CFIFO programmed to ‘continuous-scan low level gated external trigger mode’.
2) Command 2 has its ABORT_ST bit negated.
Assumptions:
3) There are no other CFIFOs using the serial interface.
WFT = Waiting for Trigger