2.1.5 External Trigger Signals in Analog System Builder

External trigger signals are used to control the sequencer from user‑defined logic. These signals are exported only when more than one procedure is defined in the sequencer.

External Jump Modes

Two external jump modes are available:
  • Manual mode:

    The system completes the operation in the current timeslot and then waits for an external trigger signal before advancing to the next slot. This mode is enabled when ASSC_XMODE = 1.

  • Auto‑forwarding mode:

    The system completes the operation in the current jump slot and automatically advances to the next slot. This continues until the sequence reaches slot 63, after which sampling resumes at slot 0. If the operation is STOP or POWERDOWN, the sequencer halts until another jump to a different slot is initiated. This mode is enabled when ASSC_XMODE = 0.

The following tables list the external trigger control and status signals provided by the Analog System Builder and describe the function of each signal. All signals described in this section are active high.

Table 2-5. External Trigger Control Signal
NameTypeDescription
ASSC_XMODEINPUTExternal trigger mode select. When set to logic 1, the analog sample sequence controller (ASSC) uses the ASSC_XTRIG signal to transition and complete the current sequence timeslot. When set to logic 0 (default automated operation), the internal timeslot counter automatically advances to the next sequence number.
ASSC_XTRIGINPUTExternal trigger input. When ASSC_XMODE is logic 1 and this signal is asserted for exactly one clock cycle, the ASSC transitions to and completes the current sequence timeslot. When ASSC_XMODE is logic 0, this signal is ignored. When using external triggering, monitor the ASSC_DONE signal to determine when ASSC_XTRIG can be asserted again.
ASSC_SEQJUMPINPUTSequence jump enable. When asserted, the sequencer jumps to the sequence number specified on ASSC_SEQIN after the current sequence timeslot completes.
ASSC_SEQIN[5:0]INPUTSequence number input. Used with ASSC_SEQJUMP to select the target sequence number. These inputs can be driven by external user logic or statically tied to logic 0 or logic 1.
ASSC_SEQOUT[5:0]OUTPUTSequence number output. Indicates the current sequence timeslot.
ASSC_SEQCHANGEOUTPUTSequence change indicator. Asserted to indicate that the ASSC_SEQOUT value will change on the next rising edge of the system clock.
ADC_CHNUMBER[4:0]OUTPUTChannel number currently being sampled by the analog‑to‑digital converter (ADC). Refer to the Analog System Builder log file to determine how logical channel numbers map to specific peripherals.
ASSC_SAMPFLAGOUTPUTSample function flag. Indicates that the sample operation is active for the currently selected ADC channel.