SPRUJ79 November 2024 F29H850TU , F29H859TU-Q1
The WADI's signal analysis block (see Figure 19-7) generates error events related to SIG1 and SIG2 that can be used to start the SSS block. The SSS block essentially provides a waveform pattern generation based off the WADI block signal analysis events. The SSS has custom configurations for how long to hold a signal low or high. The trigger or multiple trigger configuration block is how the SSS is enabled. The output event + output event trigger + duration + link configuration block are flexible settings that can be used to control the outputs, control which events triggers the outputs, control how long to hold the outputs in a high or low state, and allows cyclic signal generation. For example, if an error event occurs from the WADI block's signal analysis the SSS can output a pattern of high and low signals in a cyclic manner or perform the pattern of outputs once.
Each WADI's block signal analysis events can be used to start the SSS block. There are a total of eight configurable events (SSS_EVTnCFG[EVTn]) that can be used to compare against the trigger event (SSS_EVTTRIG) for SSS to start. Each configurable event holds the settings for all WADI blocks 1 to n. The trigger event triggers the start of the SSS if the trigger event matches one of the configured SSS events (SSS_EVTnCFG[EVTn]). Once the trigger event is met with the SSS event, the signal SIGn is overwritten with the configurations defined in the SSS output event configuration (SSS_BLKSOUTEVTnCFG[OUTEVTn]). The SSS output event can either set the output high or low. After defining the output event configurations, the SSS maps the output event to the WADI block's signal output.
Steps for output event configuration (see Figure 19-8) for WADI block 1 and 2 example:
There are four common ways to configure the SSS.
Figure 19-9 is a general diagram of configuring the SSS for single trigger with a single pattern of output events. Each output event can be configured to trigger on different events. For example, OUTEVT1 can be triggered on EVT1, EVT2, EVT3, and so on, using SSS_OUTEVTnTRIGCFG. To configure the duration of the output event, that is done through the SSS_OUTEVTnDUR.
Each output event has a fixed time of activation unless the output event is configured to be always high or low. This time is configured using the SSS_OUTEVTnDUR count that is configured by user and starts down-counting once trigger to activate the output event is met. Once the counter reaches 0, the output event is removed and delay word is reloaded for next activation. User can configure the count to 0xFF_FFFF, which is the maximum count and that is used to keep the output event continuously active. This is a special setting used for driving fixed value safe state output.
In case the subsequent sequence word is configured to be linked and shares the outputs, then make sure that before configuring the fixed overrides to 0xFF_FFFF (to delay count), the configuration either changes the output sharing or link condition of subsequent sequence word to avoid an unpredictable condition.
By hardware design, the delay condition overrides and the subsequent sequence word steps are ignored if delay count is configured to be 0xFF_FFFF.
If the second trigger to occur while sequence word is active then count is re-initialized to configured count and down-count is restarted again. Thus extending the sequence word application to related outputs.
Sequence delay setting is an independent word for each sequence word, SSS_SEQUENCE_DELAYx. The setting is a 24-bit setting that allows a delay of up to 40ms (400MHz input clock - without division) that is sufficient to drive the intermediate state of switch activations in present topologies.
Figure 19-10 shows multiple trigger with single pattern output events.
For configuring multiple triggers, in Figure 19-10, EVT1 must occur before moving onto the second event trigger. Once that event has occurred, then EVT2 must happen for the SSS to start.
Figure 19-11 shows a multiple trigger configuration before the start of the SSS and linking output events to each other to generate a single pattern of output events. For example, if the desired output is four output events high, low, high, low, the SSS can do this with linking output events to one another. The linking can be done through the SSS_OUTPUTEVTnLINKCFG.
To generate a cyclic pattern of output events, Figure 19-12, you can do so by linking the output events in a circular fashion. For example if the waveform generation pattern requires a continuous cyclic pattern of high, low, high, low. The output events 1, 2, 3, 4 can be used. Then linking output events 1 → 2 , 2 → 3, 3 → 4, then configure output event 1's link to be output event's 4. This creates the cycle of the pattern generation to continuously output this linking of output events.
Configuration of multiple triggers
In intricate switch topologies, a single event can not reflect the full condition to trigger the SSS. The topology can need two or more states to fully detect the failure condition before starting the safe state sequences. In such cases, the SSS allows linking multiple trigger events together. The register to configure multiple triggers is SSS_TRIGEVT1_4CFG and SSS_TRIGEVT5_8CFG.
| Event Word Select Combination | Words Combination for Sequences | Trigger Numbering | Action for Event Word Compare | |||
|---|---|---|---|---|---|---|
| Event 4 | Event 3 | Event 2 | Event 1 | Trig# (EVT#, next EVT#,...) | ||
| 0 | 0 | 0 | 0 | 0 | NA | None of the event words are used and safe-sequencer is not used. |
| 1 | 1 | 1 | 1 | 1+1+1+1 | T4(EVT4), T3(EVT3), T2(EVT2), T1(EVT1) | Each event trigger is independently configured and has individual sequence. |
| 0 | 1 | 1 | 1 | 1+1+1 | T3(EVT3), T2(EVT2), T1(EVT1) | Three triggers based on event as shown, fourth word is not used. |
| 0 | 0 | 1 | 1 | 1+1 | T2(EVT2), T1(EVT1) | Two triggers based on trigger event as shown. |
| 0 | 0 | 0 | 1 | 1 | T1(EVT1) | One trigger is used based on Event 1. |
| 1 | 1 | 1 | 9 | 1+1+2 | T3(EVT4), T2(EVT3), T1(EVT1, EVT2) | Two of the events are used together and other two triggers are independent triggers. Create up-to 3 possible event triggers. |
| 0 | 1 | 1 | 9 | 1+2 | T2(EVT3), T1(EVT1, EVT2) | Two triggers. One independent trigger and the other on event 1 and event 2 occurring. |
| 0 | 0 | 1 | 9 | 2 | T1(EVT1, EVT2) | Single trigger based on event 1 followed by event 2. |
| 1 | 9 | 1 | 9 | 2+2 | T2(EVT3, EVT4), T1(EVT1, EVT2) | Two pairs of events independently checked as two o/p sequences are correspondingly triggered independently. Event order applicable only between consecutive numbers 1 and 2. |
| 1 | 1 | 9 | 9 | 1+3 | T2(EVT4), T1(EVT1, EVT2, EVT3) | Three trigger events are linked and can be checked in order 1, 2, then 3. The fourth event word is independent. Thus two possible triggers. |
| 0 | 1 | 9 | 9 | 3 | T1(EVT1, EVT2, EVT3) | 3 trigger events |
| 1 | 9 | 9 | 9 | 4 | T1 (EVT1, EVT2, EVT3, EVT4) | All 4 events are indicated in consecutive increasing order. Events are checked in order. |
| Any other combination | Sequence as per configuration | Events linked is 0x9 | In case 0x1, the trigger word can cause the trigger. In case 0x9, the trigger word can relay the event to next event in order. | |||
The SSS does not have to be used, and output can be driven by WADI block instead. However both settings are not to be used simultaneously.