ST10F280_12 datasheet(92/239 Pages) STMICROELECTRONICS

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PWM module

ST10F280

92/239

Doc ID 8673 Rev. 3

11.2.6

XPOLAR Register (polarity of the XPWM channel)

XPOLAR

Address:

0xEC04h

Reset:

0x0000h

Type:

R/W

Software control of the XPWM outputs

In an application the XPWM output signals are generally controlled by the XPWM module.

However, it may be necessary to influence the level of the XPWM output pins via software

either to initialize the system or to react on some extraordinary condition, e.g. a system fault

or an emergency.

Clearing the timer run bit PTRx stops the associated counter and leaves the respective

output at its current level.

The individual XPWM channel outputs are controlled by comparators according to the

formula:

●

PWM output signal = [PTx]

≥ [PWx shadow latch].

So whenever software changes registers XPTx, the respective output will reflect the

condition after the change. Loading timer XPTx with a value greater than or equal to the

value in XPWx immediately sets the respective output, a XPTx value below the XPWx value

clears the respective output.

Note:

To prevent further PWM pulses from occurring after such a software intervention the

respective counter must be stopped first.

XPOLAR.3 XPOLAR.2 XPOLAR.1 XPOLAR.0

R/W

XPOLAR.x XPOLAR Channel x polarity Bit

0: Polarity of Channel x is normal

1: Polarity of Channel x is inverted

ST10F280 Datasheet(PDF) 92 Page - STMicroelectronics