PXD10RM Datasheet, PDF (1163/1332 Pages) Freescale Semiconductor, Inc – PXD10 Microcontroller

CLK
PWM
FB_sample
FB at pin
Counter
T_diff
T_sample
4
4
3
2
1
0
4
MCSDIn[SDIF[sd ]] interrupt flag
T_sample
T_diff
PWM
FB at pin
FB_Sample
:Sample and synchronization delay
:Delay between FB at pin and the internal PWM signal
:Signal from motor controller
:This is the signal directly after the input driver of the pad s ignal
:Pad signal after sampling and synchronization
Figure 35-34. Example for MCSDTO[TOUT] = 4
• Hence, if PWM != FB, the timer starts counting if the short-circuit detector is enabled at least one
clock cycle before (see MCSDE0, MCSDE1 or MCSDE2”)
• If PWM == FB, the timer stops and is reset to the time-out value MCSDTO[TOUT] in order to be
ready for the next transaction
• IF PWM != FB and the timer state is larger or equal MCSDTO[TOUT], than
— One of the interrupt flags MCSDI0[SDIF], MCSDE1[SDIF] or MCSDI2[SDIF] is set in order
to flag a short-circuit.
— The interrupt flag is cleared by writing one, by reset or by disabling the short-circuit detector
— The timer is stopped and reloaded with the time-out value MCSDTO[TOUT] in order to be
ready for the next transaction
• If a short-circuit detector is disabled (MCSDEn[SDEN[sd]] == 0), the related short-circuit detector
counter is halted and preloaded with the register value of MCSDTO[TOUT]. The related bit in
MCSDIn[SDIF[sd]] of this specific short-circuit detector is set to 0. This means that, if all
short-circuit detectors are disabled, all bits of MCSDIn stay at 0. No interrupt from the detector can
be generated independently of the interrupt mask in MCSDIENn.
• In case of low power-modes, the state of the short-circuit detector is frozen. After exit of the low
power mode, the short-circuit detector will resume operation from the previous state. If the
short-circuit detector should restart with defined state (counter value = MCSDTO[TOUT], than the
related detector shall be disabled and enabled again. This will reload the counter with the
MCSDTO[TOUT] value and restart the short-circuit detector.
Freescale Semiconductor
PXD10 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
35-35