SPRUJ79 November 2024 F29H850TU , F29H859TU-Q1
The error pin output (ERR_O/ERRORSTS) is used to signal an external agent to intervene because of an error. Each error event input can be programmed, via software, to influence the error pin output (using the Error Group N Error Pin Influence Set Register). The error pin output is active low or PWM based on the Error Pin Control Register[7-4] PWM_EN field. This bit field can only be modified when the ESM is disabled, based on the Global Enable register.
During Power-Оn Reset (POR), the error pin is active (asserted low) and the device drives this using a weak internal pull-down. The I/O is under the control of the device. When POR is removed from the ESM, error pin is driven by internal pull-down so the device can hand over control to the ESM. The user can also add an external pull-down that is only active when the device is in reset.
During a warm reset the state of the error pin is unchanged, that is the error pin logic is only reset by a POR. The device leaves the I/O active during a warm reset.
Figure 7-12 describes the behavior of the Error Pin. Not shown is that a reset (Power-On-Reset only) immediately transitions the Error pin to the ESM_RESET state and a Global Soft Reset immediately transitions 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 7.5 for how to clear level and pulse pending events). The second is the CLEAR event meant to de-assert the Error Pin.
Figure 7-12 Error Pin State
FlowchartIf an error event happens that has been programmed to influence the Error Pin, the Error Pin asserts (active low) for a minimum time as programmed (using the Error Pin Counter Pre-Load Register). For the Error Pin to de-assert, the following 3 things must happen : 1. The Minimum Time Interval must expire 2. The event that caused the Error Pin to assert must be cleared (see section for Interrupt Handling) 3. A CLEAR must be written to the Error Pin Control Register. Note that step 3 can only happen after step 2, but either (or both) of those steps can occur before or after step 1.
Figure 7-13 shows a typical error pin assertion.
If, during the minimum time, CLEAR is written to the error key, then the error pin de-asserts after the minimum time interval, as shown in Figure 7-14.
When 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.
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 in Figure 7-17), but are not necessary. No matter how many Error Events occur nor when (or how many) CLEAR events occur, the Error Pin is always asserted for at least the Minimum Interval.
If 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 Event occurs, the ESM goes back to the ESM_ERROR state. The Minimum Interval does not reset, but a new CLEAR event is required.
Table 7-10 shows some common scenarios of how the error pin as well as the two associated registers (Error Pin Control Register and Error Pin Status Register) are set.
| Scenario | Error Pin State Value | KEY | Error Pin Register Status | Additional Notes |
|---|---|---|---|---|
| POR Asserted | 0 | N/A | N/A | Registers are inaccessible. Device disables the I/O and pulls down internally. |
| After de-assertion of POR | 1 | 0x0 (Normal Mode) | 0x1 | - |
| After de-assertion of Warm Reset (error was not asserted when reset asserted) | 1 | 0x0 (Normal Mode) | 0x1 | - |
| After de-assertion of Warm Reset (error was asserted when reset asserted) | 0 | 0x0 (Normal Mode) | 0x0 | - |
| Force error pin | 0 | 0xA (Force Error Mode) | 0x0 | Forcing error on the pin using software. |