SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
The trip-zone signals at pin TZ0 to TZ5 is an active-low input signal. When the pin goes low, it indicates that a trip event has occurred. Each EPWM module can be individually configured to ignore or use each of the trip-zone pins. Which trip-zone pins are used by a particular EPWM module is determined by the EPWM_TZSEL register for that specific EPWM module. The trip-zone signal may or may not be synchronized to the system clock (FICLK). A minimum of 1 FICLK low pulse on the TZ0 to TZ5 inputs is sufficient to trigger a fault condition in the EPWM module. The asynchronous trip makes sure that if clocks are missing for any reason, the outputs can still be tripped by a valid event present on the TZ0 to TZ5 inputs.
The TZ0 to TZ5 inputs can be individually configured to provide either a cycle-by-cycle or one-shot trip event for a EPWM module. The configuration is determined by the EPWM_TZSEL[5-0] CBCk and EPWM_TZSEL[13-8] OSHTk bit field (where k = 0 to 5 corresponds to the trip pin), respectively.
The specified condition on the pins is automatically cleared when the EPWM time-base counter reaches zero (EPWM_TBCNT[15-0] TBCNT = 0000h) if the trip event is no longer present. Therefore, in this mode, the trip event is cleared or reset every PWM cycle. The EPWM_TZFLG[1] CBC flag bit will remain set until it is manually cleared by writing to the EPWM_TZCLR[1] CBC bit. If the cycle-by-cycle trip event is still present when the EPWM_TZFLG[1] CBC bit is cleared, then it will again be immediately set.
The action taken when a trip event occurs can be configured individually for each of the EPWM output pins by way of the EPWM_TZCTL[1-0] TZA and EPWM_TZCTL[3-2] TZB register bit field. One of four possible actions, shown in Table 12-278, can be taken on a trip event.
EPWM_TZCTL[1-0] TZA and/or EPWM_TZCTL[3-2] TZB | EPWMxA and/or EPWMxB | Comment |
---|---|---|
0 | High-Impedance | Tripped |
1h | Force to High State | Tripped |
2h | Force to Low State | Tripped |
3h | No Change | Do Nothing. No change is made to the output. |
Example of EPWM Trip-Zone Configurations
A one-shot trip event on
TZ0 pulls both EPWM1A, EPWM1B low and also forces EPWM2A and EPWM2B high.