15.4.3.3.4 Output Override in Push-Pull and Independent Modes

When operating in Push-Pull or Independent Output modes, there is no logic that enforces a complementary relationship between the PWMxH and PWMxL signals. It is possible to drive both pins to an Active state with a software or hardware (PCI) override. This Output state may or may not be desirable, depending on the external circuit that is controlled by the PWM Generator. Therefore, care must be taken when selecting the pin override values. Many push-pull applications require an equal pulse on both the PWMxH and PWMxL outputs to avoid a DC component. If the application is sensitive to this, perform software overrides after two complete timer cycles have taken place. Hardware PCI overrides should be configured to take effect after both timer cycles in the push-pull sequence have occurred. This can be accomplished by using the STEER signal, routed through the event logic to a pin, which can then be selected as an input to the PCI block.

Figure 15-19. Override and SWAP Signal Flow, Push-Pull Output Mode

Table 15-9 shows the rules for pin override conditions. The Active state is a ‘1’ on the output pin and the Inactive state is a ‘0’. An ‘x’ denotes a ‘don’t care’ input; ~PWM indicates the complementary output of the PWM Generator's output.

Table 15-9. Override and SWAP Behavior in Push-Pull, Independent Output Modes
Source	SWAP	OVRENH	OVRENL	OVRDAT[1:0]	FFDAT[1:0]	CLDAT[1:0]	FLTDAT[1:0]	DBGDAT[1:0]	PWMxH  Pin State	PWMxL  Pin State
Debug Override
DEBUG	`x`	`x`	`x`	`xx`	`xx`	`xx`	`xx`	`00`	Inactive	Inactive
								`01`	Inactive	Active
								`10`	Active	Inactive
								`11`	Active	Active
Fault Override – Debug Override Must be Inactive
PCI FLT	`x`	`x`	`x`	`xx`	`xx`	`xx`	`00`	`xx`	Inactive	Inactive
							`01`		Inactive	Active
							`10`		Active	Inactive
							`11`		Active	Active
Current Limit Override – Fault and Debug Overrides Must be Inactive
PCI CL	`x`	`x`	`x`	`xx`	`xx`	`00`	`xx`	`xx`	Inactive	Inactive
						`01`			Inactive	Active
						`10`			Active	Inactive
						`11`			Active	Active
Feed-Forward Override – Software, Current Limit, Fault and Debug Overrides Must be Inactive
PCI FF	`x`	`0`	`0`	`xx`	`00`	`xx`	`xx`	`xx`	Inactive	Inactive
					`01`				Inactive	Active
					`10`				Active	Inactive
					`11`				Active	Active
Software Override – Current Limit, Fault and Debug Overrides Must be Inactive
Software Override	`0`	`0`	`1`	`x0`	`xx`	`xx`	`xx`	`xx`	PWMH	Inactive
		`0`	`1`	`x1`					PWMH	Active
		`1`	`0`	`0x`					Inactive	PWML
		`1`	`0`	`1x`					Active	PWML
	`1`	`0`	`1`	`x0`					PWML	Inactive
		`0`	`1`	`x1`					PWML	Active
		`1`	`0`	`0x`					Inactive	PWMH
		`1`	`0`	`1x`					Active	PWMH
	`x`	`1`	`1`	`00`					Inactive	Inactive
				`01`					Inactive	Active
				`10`					Active	Inactive
				`11`					Active	Active