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US 7,003,032 B2Granted
Generation of multiple independent high resolution pulse width modulations
AssigneeDelphi Technologies, Inc.
InventorsMelissa Marie Klemish, Robert Brady Gager, Lamar Harold McLouth
Life of this patent
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Abstract
A method for generating multiple high-resolution PWM signals in which software interrupts are introduced at predetermined intervals to generate multiple high-resolution PWM signals from a conventional microprocessor. The software determines the purpose of the interrupt in an interrupt subroutine. An interrupt occurs when a compare register equals the timer. Another interrupt occurs when the timer overflows. The interrupts are the key to generating the multiple high-resolution PWM signals.
Claims13
A method for generating multiple high-resolution pulse width modulated (PWM) signals comprising the steps of:
- receiving data representative of duty cycle values;
- sorting said duty cycle values in a duty cycle table to generate a PWM generation table;
- generating an interrupt from a capture and compare interrupt defined by a match between a timer value and a duty cycle register;
- generating an interrupt from a timer overflow;
- generating multiple PWM signals as defined by said PWM generation table upon detection of said capture and compare interrupt;
- and
- returning to a beginning point in said PWM generation table upon generation of a timer overflow interrupt,
- wherein said step of sorting said duty cycle values further comprises the steps of:
- sorting said duty cycle values along with data stored in a port table containing port pin assignments for each duty cycle value;
- and
- sorting said duty cycle values along with data stored in a bit-mask table containing bit-mask assignments corresponding to a specific port pin assignment.
8 more elements
A system for generating multiple high-resolution pulse width modulated (PWM) signals comprising:
- a microprocessor having a timer, said microprocessor for receiving duty cycle values;
- a communication bus for sending duty cycle values to said microprocessor;
- a capture and compare module operative to selectively generate software interrupts as a function of timer and duty cycle values in communication with said microprocessor;
- a duty cycle table at a predetermined location in memory of said microprocessor, said duty cycle table for storing said duty cycle values;
- a port table having port assignments corresponding to a duty cycle value in said duty cycle table, said port table being stored in memory of said microprocessor;
- a bit-mask table having bit-mask assignments corresponding to a port assignment in said port table, said bit-mask table being stored in memory of said microprocessor;
- a PWM generation table created by sorting said duty cycle table, said port table and said bit-mask table upon receipt of all duty cycle values;
- and
- an interrupt routine that is entered only upon generation of an interrupt wherein said interrupt routine allows said microprocessor to write a predetermined duty cycle value from said PWM generation table to a predetermined port assignment from said PWM generation table.
6 more elements
A method for generating multiple high-resolution pulse width modulated (PWM) signals in a system having a microprocessor, a communication bus, and a timer, said method comprising the steps of:
- receiving a plurality of duty cycle values at said microprocessor;
- placing said duty cycle values in a duty cycle table wherein each duty cycle value has a corresponding port assignment in a port table and a corresponding bit-mask assignment in a bit-mask table, said port and bit-mask tables being embedded in software in said microprocessor;
- generating a PWM generation table by sorting said duty cycle, port and bit-mask tables in a background task of said microprocessor;
- generating a capture and compare interrupt when a source of said interrupt is when a timer value matches a duty cycle value;
- generating a timer overflow interrupt when a source of said interrupt is an overflow of said timer;
- receiving an interrupt at said microprocessor;
- determining a source for said received interrupt;
- writing predetermined values to a plurality of pins on said microprocessor based on said source for said interrupt;
- writing values to a plurality of ports wherein said values are taken directly from said PWM generation table during a capture and compare interrupt;
- writing a low value to a plurality of pins during a timer overflow interrupt;
- and
- returning to a beginning point in said PWM generation table upon generation of a timer overflow interrupt.
9 more elements
A method for generating multiple high-resolution pulse width modulated (PWM) signals comprising the steps of:
- receiving data representative of duty cycle values;
- sorting said duty cycle values in a duty cycle table to generate a PWM generation table;
- generating an interrupt from a capture and compare interrupt defined by a match between a timer value and a duty cycle register;
- generating an interrupt from a timer overflow;
- generating multiple PWM signals as defined by said PWM generation table upon detection of said capture and compare interrupt;
- and
- returning to a beginning point in said PWM generation table upon generation of a timer overflow interrupt,
- wherein said step of sorting said duty cycle values to generate a PWM generation table further comprises the step of placing an invalid duty cycle value at the end of the PWM generation table, wherein said invalid duty cycle value is a value that is not equal to said timer value for allowing the timer to overflow.
5 more elements
A method for generating multiple high-resolution pulse width modulated (PWM) signals comprising the steps of:
- receiving data representative of duty cycle values;
- sorting said duty cycle values in a duty cycle table to generate a PWM generation table;
- generating an interrupt from a capture and compare interrupt defined by a match between a timer value and a duty cycle register;
- generating an interrupt from a timer overflow;
- generating multiple PWM signals as defined by said PWM generation table upon detection of said capture and compare interrupt;
- and returning to a beginning point in said PWM generation table upon generation of a timer overflow interrupt,
- wherein said step of generating an interrupt further comprises the step of writing values to a plurality of port pins directly from said PWM generation table.
4 more elements
A method for generating multiple high-resolution pulse width modulated (PWM) signals comprising the steps of:
- receiving data representative of duty cycle values;
- sorting said duty cycle values in a duty cycle table to generate a PWM generation table;
- generating an interrupt from a capture and compare interrupt defined by a match between a timer value and a duty cycle register;
- generating an interrupt from a timer overflow;
- generating multiple PWM signals as defined by said PWM generation table upon detection of said capture and compare interrupt;
- and
- returning to a beginning point in said PWM generation table upon generation of a timer overflow interrupt,
- wherein said step of generating an interrupt from a timer overflow further comprises the step of resetting a plurality of port pins to low.
5 more elements
Dependencies are inferred from the claim text.