Pulse Width Modulator (PWM)
up from zero to the preset value, count back down to zero, and then repeat the process. This
will produce center-aligned PWM signals (that is, the middle of the high/low period of the PWM
signals produced by the generator will occur at the same time).
When the PWM generator parameters (period and pulse width) are modified, their affect on
the output PWM signals can be delayed. In synchronous mode, the parameter updates are not
applied until a synchronization event occurs. This allows multiple parameters to be modified
and take affect simultaneously, instead of one at a time. Additionally, parameters to multiple
PWM generators in synchronous mode can be updated simultaneously, allowing them to be
treated as if they were a unified generator. In non-synchronous mode, the parameter updates
are not delayed until a synchronization event. In either mode, the parameter updates only
occur when the counter is at zero to help prevent oddly formed PWM signals during the update
(that is, a PWM pulse that is too short or too long).
The PWM generator can either pause or continue running when the processor is stopped via
the debugger. If configured to pause, it will continue to count until it reaches zero, at which
point it will pause until the processor is restarted. If configured to continue running, it will keep
counting as if nothing had happened.
The
ui32Config
parameter contains the desired configuration. It is the logical OR of the follow-
ing:
PWM_GEN_MODE_DOWN
or
PWM_GEN_MODE_UP_DOWN
to specify the counting
mode
PWM_GEN_MODE_SYNC
or
PWM_GEN_MODE_NO_SYNC
to specify the counter load
and comparator update synchronization mode
PWM_GEN_MODE_DBG_RUN
or
PWM_GEN_MODE_DBG_STOP
to specify the debug
behavior
PWM_GEN_MODE_GEN_NO_SYNC
,
PWM_GEN_MODE_GEN_SYNC_LOCAL
,
or
PWM_GEN_MODE_GEN_SYNC_GLOBAL
to specify the update synchronization mode
for generator counting mode changes
PWM_GEN_MODE_DB_NO_SYNC
,
PWM_GEN_MODE_DB_SYNC_LOCAL
,
or
PWM_GEN_MODE_DB_SYNC_GLOBAL
to specify the deadband parameter syn-
chronization mode
PWM_GEN_MODE_FAULT_LATCHED
or
PWM_GEN_MODE_FAULT_UNLATCHED
to
specify whether fault conditions are latched or not
PWM_GEN_MODE_FAULT_MINPER
or
PWM_GEN_MODE_FAULT_NO_MINPER
to
specify whether minimum fault period support is required
PWM_GEN_MODE_FAULT_EXT
or
PWM_GEN_MODE_FAULT_LEGACY
to specify
whether extended fault source selection support is enabled or not
Setting
PWM_GEN_MODE_FAULT_MINPER
allows an application to set the minimum dura-
tion of a PWM fault signal. Faults will be signaled for at least this time even if the external fault
pin deasserts earlier. Care should be taken when using this mode since during the fault signal
period, the fault interrupt from the PWM generator will remain asserted. The fault interrupt
handler may, therefore, reenter immediately if it exits prior to expiration of the fault timer.
Note:
Changes to the counter mode will affect the period of the PWM signals produced.
and
should be called after any
changes to the counter mode of a generator.
Returns:
None.
158
April 8, 2013
Summary of Contents for Tiva TM4C123GH6PM
Page 26: ...Boot Loader 26 April 8 2013...
Page 68: ...Controller Area Network CAN 68 April 8 2013...
Page 122: ...Hibernation Module 122 April 8 2013...
Page 136: ...Inter Integrated Circuit I2C 136 April 8 2013...
Page 152: ...Memory Protection Unit MPU 152 April 8 2013...
Page 174: ...Pulse Width Modulator PWM Returns None 174 April 8 2013...
Page 196: ...Synchronous Serial Interface SSI 196 April 8 2013...
Page 222: ...System Control 222 April 8 2013...
Page 270: ...UART 270 April 8 2013...
Page 296: ...uDMA Controller 296 April 8 2013...
Page 351: ...April 8 2013 351...