F28335_Trip-Zone Submodule Control中CBC和OSHT两种保护解释

CBC和One shot的解释在user guide SPRUG04A 的解释如下图：

• Cycle-by-Cycle (CBC):
When a cycle-by-cycle trip event occurs, the action specified in the TZCTL register is carried out
immediately on the EPWMxA and/or EPWMxB output. Table 19 lists the possible actions. In addition,
the cycle-by-cycle trip event flag (TZFLG[CBC]) is set and a EPWMx_TZINT interrupt is generated if it
is enabled in the TZEINT register and PIE peripheral.
The specified condition on the pins is automatically cleared when the ePWM time-base counter
reaches zero (TBCTR = 0x0000) if the trip event is no longer present. Therefore, in this mode, the trip
event is cleared or reset every PWM cycle. The TZFLG[CBC] flag bit will remain set until it is manually
cleared by writing to the TZCLR[CBC] bit. If the cycle-by-cycle trip event is still present when the
TZFLG[CBC] bit is cleared, then it will again be immediately set.

意思是，CBC模式就是cycle by cycle模式，他的特点是一旦触发就会立即装载TZCTL中TZA,TZB的配置的PWM状态（高，低，高阻，或者不变），但是每次PWM计数器为0的时候他会再次检测TZ引脚的输入是否仍然被触发，如果仍然被触发，就继续保护，如果不再被触发，就恢复PWM输出

• One-Shot (OSHT):
When a one-shot trip event occurs, the action specified in the TZCTL register is carried out
immediately on the EPWMxA and/or EPWMxB output. Table 19 lists the possible actions. In addition,
the one-shot trip event flag (TZFLG[OST]) is set and a EPWMx_TZINT interrupt is generated if it is
enabled in the TZEINT register and PIE peripheral. The one-shot trip condition must be cleared
manually by writing to the TZCLR[OST] bit.

One-shot总的来说区别就是，一旦触发就无法自动恢复，会始终处于保护状态，直到手动清除TZFLG中的OST位，就是在TZCLR中给OST位赋值1.