mc9s12e256 Freescale Semiconductor, Inc, mc9s12e256 Datasheet - Page 373

• Manufacturer Part Number: mc9s12e256
• Description: Hcs12 Microcontrollers 16-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

When the PWMEN bit is cleared:
11.4.8
Fault protection can disable any combination of PWM pins. Faults are generated by a logic one on any of
the FAULT pins. Each FAULT pin can be mapped arbitrarily to any of the PWM pins.
When fault protection hardware disables PWM pins, the PWM generator continues to run, only the output
pins are deactivated.
The fault decoder disables PWM pins selected by the fault logic and the disable mapping register. See
Figure
pin. Refer to
The fault protection is enabled even when the PWM is not enabled; therefore, a fault will be latched in and
will be cleared in order to prevent an interrupt when the PWM is enabled.
11.4.8.1
Each fault pin has a sample filter to test for fault conditions. After every bus cycle setting the FAULTx pin
at logic zero, the filter synchronously samples the pin once every four bus cycles. QSMP determines the
number of consecutive samples that must be logic one for a fault to be detected. When a fault is detected,
the corresponding FAULTx pin flag, FFLAGx, is set. Clear FFLAGx by writing a logic one to it.
If the FIEx, FAULTx pin interrupt enable bit is set, the FFLAGx flag generates a CPU interrupt request.
The interrupt request latch remains set until:
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11-15. Each bank of four bits in the disable mapping register control the mapping for a single PWM
The PWMx outputs will be tri-stated unless OUTCTLx = 1
The PWM counter is cleared and does not count
The PWM generator forces its outputs to zero
The PWMRF flag and pending CPU interrupt requests are not cleared
All fault circuitry remains active unless FPINEx = 0
Software output control remains active
Deadtime insertion continues during software output control
Software clears the FFLAGx flag by writing a logic one to it
Software clears the FIEx bit by writing a logic zero to it
A reset occurs
Fault Protection
Table
Fault Pin Sample Filter
11-12.
MC9S12E256 Data Sheet, Rev. 1.08
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
373