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Burst Generator

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Ivan Cenov edited this page Apr 16, 2019 · 1 revision

Burst Generator

The Burst generator produces bursts of impulses with following specification:

 ------ pulses -----
 +---+  +---+  +---+            +---+  +---+  +---+
 |   |  |   |  |   |            |   |  |   |  |   |
 |   |  |   |  |   |            |   |  |   |  |   |
-+   +--+   +--+   +------------+   +--+   +--+   +---------
  ht  lt                 it
pulses - number of the pulses in a package
ht - high time
lt - low time
it - idle time between the packages

The timer can be used to drive an output of a microcontroller or simply to change a variable holding the state. This timer is ideal for producing LED blinking with variuous number of light times.

To avoid mistakes, always use a definition of the output pin instead of its name as macro argument in macro calls.

Declaration.

Macro Description
DEFINE_BURST_GENERATOR(tag,ttype) Declares a burst generator in .c file by decalring its variables. tag is the tag of the timer, and ttype is its type.
EXTERN_BURST_GENERATOR(tag,ttype) Define external definitions in .h file. tag is the tag of the timer, and ttype is its type.

Variables.

Variable Description
BurstGeneratorCounter(tag) Counter of the timer. It is not good idea to access this avriable directly.
BurstGeneratorPulses(tag) Number of the pulses in a singel burst.
BurstGeneratorHighTime(tag) Length of the high state of the single impulse.
BurstGeneratorLowTime(tag) Length of the low state between two adjacent impulses in a burst.
BurstGeneratorIdleTime(tag) Length of the idle time between two bursts.
BurstGeneratorPulseCounter(tag) Pulse counter of the timer. Not intended for direct access.
BurstGeneratorState(tag) This variable holds the state of the timer output - BG_STATE_LOW or BG_STATE_HIGH.
BurstGeneratorFlag(tag) This flag, when true, indicates active, working timer. When false the flag indicates a stopped timer.
BurstGeneratorTick(tag) This flag is raised at every change BurstGeneratorState(tag). It can be used by the application to do something or to manipulate some output pin.

Manipulation macros.

Burst generators have two sets of manipulation macros - without or with output. The first set manipulate the output variable BurstGeneratorState(tag) only. The second set is given an argument pointing output pin. These macros directly manipulate this output in addition to manipulating BurstGeneratorState(tag). This way output bursts are more exact in time.

Macros without output pin

Macro Description
SetBurstGenerator(tag,pulses,ht,lt,it) This macro starts a burst generator with tag tag. The arguments set values for BurstGeneratorPulses(tag), BurstGeneratorHighTime(tag), BurstGeneratorLowTime(tag) and BurstGeneratorIdleTime(tag). BurstGeneratorFlag(x) is set and BurstGeneratorTick(x) cleared. BurstGeneratorState(x) is set to BG_STATE_LOW - it will become BG_STATE_HIGH when next RTC_TICK comes. The macro disables the interrupts and enables them at the end.
SetBurstGeneratorI(tag,pulses,ht,lt,it) This macro does the same as SetBurstGenerator(tag,pulses,ht,lt,it) but does not touch the interrupts.
ResetBurstGenerator(tag) This macro stops the timer by clearing BurstGeneratorFlag(x) and BurstGeneratorTick(x). It also sets BurstGeneratorState(x) to BG_STATE_LOW. This macro does not touch the interrupts.
ClearBurstGenerator(tag) This macro clears all variables of the timer. It does not touch the interrupts.
StopBurstGenerator(tag) This macro stops the timer by clearing BurstGeneratorFlag(x) and BurstGeneratorTick(x). It also sets BurstGeneratorState(x) to BG_STATE_LOW. The macro disables the interrupts and enables them at the end.
TickBurstGenerator(tag) This macro is called at every RTC_TICK. It decrements by one BurstGeneratorCounter(tag), manupulates the other variables and accordingly sets or clears BurstGeneratorState(tag).

Macros with output pin

Macro Description
SetBurstGeneratorWithOutput(tag,pulses,ht,lt,it,out) This macros does the same as SetBurstGenerator(tag,pulses,ht,lt,it). In addition, it clears the output out.
SetBurstGeneratorIWithOutput(tag,pulses,ht,lt,it,out) This macros does the same as SetBurstGeneratorI(tag,pulses,ht,lt,it). In addition, it clears the output out.
ResetBurstGeneratorWithOutput(tag,out) This macros does the same as ResetBurstGenerator(tag). In addition, it clears the output out.
ClearBurstGeneratorWithOutput(tag) This macros does the same as ClearBurstGenerator(tag). In addition, it clears the output out.
StopBurstGeneratorWithOutput(tag,out) This macros does the same as StopBurstGenerator(tag). In addition, it clears the output out.
TickBurstGeneratorWithOutput(tag,out) This macros does the same as TickBurstGenerator(tag). In addition, it manipulates the output out accordingly to BurstGeneratorState(tag).

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