SPRUJ17I March 2022 – August 2025 AM2631 , AM2631-Q1 , AM2632 , AM2632-Q1 , AM2634 , AM2634-Q1
The Error Pin Output is used to signal an external agent that it needs to (or may need to) intervene because of an error. Each Error Event Input can be programmed, via software, to influence the Error Pin Output (Error Group N Error Pin Influence Set Register (Base Address + 0x400 + N*0x20 + 0x14)). The ESM does not actually incorporate an I/O, this must be done at the SoC level. The Error Pin Output is active low or PWM based on the Error Pin Control register pwm_en field. This pwm_en field should only be modified when the ESM is disabled, based on the Global Enable register.
During Power-On-Reset, the Error Pin is active (asserted low). It is expected that the SoC drives this via a weak internal pull-down. The I/O is under the control of the SoC. When POR is removed from the ESM, it will be driving the Error Pin so the SoC can hand over control to the ESM. The customer may also add an external pull-down that is only active when the SoC is in reset.
During a Warm Reset the state of the Error Pin is unchanged (i.e. the Error Pin logic is only reset by a Power-On-Reset). The SoC should leave the I/O active during a warm reset.
The I/O input from the cell should be looped back to the err_i input. In this way, the status of the error I/O can be directly observed from the I/O buffer loopback path, instead of just from the internal state to the ESM.
The isolation value for the err_o output of ESM is active (0).
Figure 13-274 describes the behavior of the Error Pin. Not shown is that a reset (Power-On-Reset only) will immediately transition the Error pin to the ESM_RESET state and a Global Soft Reset will immediately transition the Error pin to the ESM_IDLE state. A Pending Error Event is any error event with the raw state set and the Error Pin Influence enabled. There are two types of “clear” events associated with servicing the Error Pin. The first is to clear the status of the pending event (see section Section 13.6.3.4.9) for how to clear level and pulse pending events). The second is the CLEAR event meant to de-assert the Error Pin.
Figure 13-274 ESM Error
Pin State FlowchartIf an error event happens that has been programmed to influence the Error Pin, the Error Pin will assert (active low) for a minimum time (as programmed by the Error Pin Counter Pre-Load Register (Base Address + 0x4C)). In order for the Error Pin to de-assert, the following 3 things must happen
Step 3 should happen after step 2, but either (or both) of these steps may happen before or after step 1.
Figure 13-275 ESM Error
Pin AssertionIf, during the minimum time, CLEAR is written to the error key, then the error pin will de-assert after the minimum interval.
Figure 13-276 ESM Error
Pin Assertion with CLEAR during Minimum IntervalIf CLEAR is not written till after the minimum interval, the error pin will de-assert when CLEAR is written. This is regardless of whether the error event itself is removed before or after the minimum interval, as shown by the dotted line in Figure 13-277
Figure 13-277 ESM Error
Pin Asserting with CLEAR after Minimum IntervalWhen in the ESM_ERROR state and a CLEAR event happens, if there are still pending error events, the ESM stays in the ESM_ERROR state with the error pin asserted. Multiple error events when in the ESM_ERROR state do not reset the minimum interval counter.
Figure 13-278 ESM Error
Pin Asserting with Interval Reset by Additional Error Event(s)A CLEAR event causes a re-evaluation of whether there are any pending error events. As such, a single CLEAR can be used to clear the error pin after multiple error events. Multiple CLEAR events can occur (such as the one with the dotted arrow shown in Figure 13-279), but are not necessary. No matter how many error events occur nor when (or how many) CLEAR events occur, the error pin will always be asserted for at least the minimum interval
Figure 13-279 ESM Error
Pin Asserting with Single CLEAR for Multiple EventsIf all error events are cleared and the ESM is in the ESM_WAIT state, waiting for the minimum interval to expire, and a new error interrupt event occurs, the ESM will go back to the ESM_ERROR state. The minimum interval will not reset, but a new CLEAR event will be required.
Figure 13-280 ESM Error
Pin Asserting with New Error During Minimum Time Interval