Claims:1. A microcontroller-based motor controller with real time clock (RTC) based timer feature comprising:
a real-time clock RTC chip; and
a toggle switch, wherein
the RTC chip communicates on synchronous serial communication line with the microcontroller through which the microcontroller reads the RTC data, and based on which, it provides automatic switching of motor.
2. The microcontroller-based motor controller as claimed in claim 1, wherein the toggle-switch is read though a port pin configured as digital input by the microcontroller.
3. The microcontroller-based motor controller as claimed in claim 1, wherein the micro-controller is connected with real-time clock (RTC) chip with a synchronous serial communication interface, where there is a clock line and a data line, for which two of the port pins of the microcontroller is required.
4. The microcontroller-based motor controller as claimed in claim 1, wherein inputs from the toggle switch and the RTC data line are multiplexed to use one single port pin without any additional hardware.
5. The microcontroller-based motor controller as claimed in claim 1, wherein the RTC chip has an 8-byte data structure inside, with each byte containing different time parameters, which are any or a combination of hours, minutes, seconds, years, months, and days.
6. The microcontroller-based motor controller as claimed in claim 1, wherein the RTC time data is updated reliably, and wherein the toggle switch, on being actuated, is adapted to interrupt the communication.
, Description:FIELD OF INVENTION
[0001] The present invention relates, in general, to a low-cost microcontroller-based motor controller with real-time clock based timer. More particularly, the present invention relates to a motor controller with real-time clock based timer having a physical switch for user to switch on or off the RTC mode.

BACKGROUND
[0002] The controller unit can be used to work with various type of motors or actuators depending on the applications. The primary function of the controller is to provide a user interface to switch on/off the motor, commonly given through push-buttons.
[0003] US7747146B2 entitled “Motor controller having a multifunction port” relates to an H-bridge for DC motor control. It claims novelty for their control circuit which receives control signal from a multifunction-port to drive the motor in either of the three different modes i.e. sleep mode, brake mode, and pulse width modulation (PWM) mode.
[0004] US20110102053A1 entitled “Method and SOC for implementing time division multiplexing of pin” refers to a method of system-on chip design with two bidirectional PAD units which enable the pins to be used in different interface modes in different times.
[0005] The present invention refers to a motor control application with real-time clock based timer feature with a scheme to multiplex the communication line for RTC data with the digital input of the switch using a single port pin without a need for any additional hardware for multiplexing. It also ensures reliability of the RTC data received by the microcontroller which can be corrupted due to random toggling of the switch by the user.
[0006] The present invention refers to a variant of such a motor controller with a feature where user can set clock times for switching on and switching off the motor in HH:MM format, say T1 and T2, respectively. So, the controller automatically turns on the motor at time T1 and turns it off at time T2. This is useful feature for the user as many applications of such motors have daily schedules depending on the scenario and after setting the times T1 and T2 the user need not worry about any manual intervention for motor switching. The inputs for T1 and T2 times can be given with the help of rotary switches. Other features in the motor controller include providing electrical protections for the motor such as over voltage, under voltage, over current, under current, etc for single phase motor. For three-phase motor applications, there are additional protections given such as unbalance, single phasing, phase reversal, etc. In order to give these protections, the motor controller needs to measure the current and voltages, so it has appropriate circuitry to enable the microcontroller to measure the signals using analogue-to-digital converter. There can be a small local display made up of 7-segment LEDs and push-buttons for navigation for the user to view current, voltage parameters, or configure different settings. There are different status LEDs to convey operational status of the controller and the motor to the user.
[0007] A very important factor is to provide a compact and low-cost solution to the user. Due to the requirements of providing several features mentioned above, designing compact and low-cost solution often translates to optimization of port pins of the microcontroller. If multiple functions can be performed using lesser number of pins without the need for additional hardware for multiplexing, then it saves cost and also helps to have a compact design.

OBJECTS OF THE INVENTION
[0008] An object of the present invention is to provide a low-cost microcontroller-based motor controller with real-time clock based timer.
[0009] Another object of the present invention is to enable multiple functions to be performed using lesser number of pins without the need for additional hardware for multiplexing, hence saving cost and also having a compact design.

SUMMARY
[0010] The present invention relates, in general, to a low-cost microcontroller-based motor controller with real-time clock based timer. More particularly, the present invention relates to a motor controller with real-time clock based timer having a physical switch for user to switch on or off the RTC mode.
[0011] In an aspect, the present disclosure provides a microcontroller-based motor controller with real time clock (RTC) based timer feature comprising: a real-time clock RTC chip; and a toggle switch, wherein the RTC chip communicates on synchronous serial communication line with the microcontroller through which the microcontroller reads the RTC data, and based on which, it provides automatic switching of motor.
[0012] In an embodiment, the toggle-switch is read though a port pin configured as digital input by the microcontroller.
[0013] In another embodiment, the micro-controller is connected with real-time clock (RTC) chip with a synchronous serial communication interface, where there is a clock line and a data line, for which two of the port pins of the microcontroller is required. The RTC data line input and the toggle switch input are multiplexed to use one single port without any additional hardware.
[0014] In another embodiment, inputs from the toggle switch and the RTC data line are multiplexed to use one single port pin without any additional hardware.
[0015] In another embodiment, the RTC chip has an 8-byte data structure inside, with each byte containing different time parameters, which are any or a combination of hours, minutes, seconds, years, months, and days.
[0016] In another embodiment, the RTC time data is updated reliably, and wherein the toggle switch, on being actuated, is adapted to interrupt the communication.

BRIEF DESCRIPTION OF THE DRAWINGS
[0017] For a fuller understanding of the nature and objectives of the invention, reference should be made to the following detailed description taken in connection with the accompanying drawings in which:
[0018] FIG. 1 shows the block diagram of the microcontroller-based motor controller of the invention illustrating the various components and interfaces thereof.
DETAILED DESCRIPTION OF THE INVENTION
[0019] In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details.
[0020] The present invention relates, in general, to a low-cost microcontroller-based motor controller with real-time clock based timer. More particularly, the present invention relates to a motor controller with real-time clock based timer having a physical switch for user to switch on or off the RTC mode.
[0021] In an aspect, the present disclosure provides a microcontroller-based motor controller with real time clock (RTC) based timer feature comprising: a real-time clock RTC chip; and a toggle switch, wherein the RTC chip communicates on synchronous serial communication line with the microcontroller through which the microcontroller reads the RTC data, and based on which, it provides automatic switching of motor.
[0022] In an embodiment, the toggle-switch is read though a port pin configured as digital input by the microcontroller.
[0023] In another embodiment, the micro-controller is connected with real-time clock (RTC) chip with a synchronous serial communication interface, where there is a clock line and a data line, for which two of the port pins of the microcontroller is required.
[0024] In another embodiment, the RTC chip has an 8-byte data structure inside, with each byte containing different time parameters, which are any or a combination of hours, minutes, seconds, years, months, and days.
[0025] FIG. 1 shows the block diagram of the microcontroller-based motor controller of the invention illustrating the various components and interfaces thereof.
[0026] The present invention refers to a variant of such a motor controller with a feature where user can set clock times for switching on and switching off the motor in HH:MM format, say T1 and T2, respectively. So, the controller automatically turns on the motor at time T1 and turns it off at time T2. This is useful feature for the user as many applications of such motors have daily schedules depending on the scenario and after setting the times T1 and T2 the user need not worry about any manual intervention for motor switching. The inputs for T1 and T2 times can be given with the help of rotary switches or using display navigation with push buttons.
[0027] The microcontroller is connected with real-time clock (RTC) chip with a synchronous serial communication interface, where there is a clock line and a data line, for which two of the port pins of the microcontroller are used. The controller can read the time data from the RTC-chip through this interface so that it can provide the daily timer feature for the motor application based on T1 and T2 settings.
[0028] There is a user controller rocker switch to select the motor operation mode, where one of the modes corresponds to the daily timer mode. The switch input is connected to the same port pin where the data-line of the serial communication interface is connected. As per the design, when the switch is kept in daily timer mode, the port pin is connected to Vdd through a pull-up resistor and for the other mode it is connected to ground.
[0029] The microcontroller starts an internal timer of 100ms to generate time windows for time division multiplexing of the port pin. At the start of the first-time window, the port pin is configured as a GPIO input port. The port status is read, and the Operation Mode of the motor is saved. After 100ms at the beginning of the second window, the port pin is configured as the data line to communicate with RTC chip. Then the clock time data is read from the RTC chip through the communication. Since the switch has pulled up the port pin, it does not hamper the serial communication as pull-up is its default state for communication. If the Operation Mode is not the timer mode, where the pin is grounded, RTC data is not required hence no communication is carried out. After another 100ms, again the port pin is configured to be a GPIO input port and the cycle continues. In this way using the single port pin, microcontroller reads the user operation mode as well as it communicates with the RTC chip to get the time data.
[0030] The RTC chip has an 8-byte data structure inside having bytes D0, D1…D7 which contain different time parameters such has hours, minutes, seconds, year, month, day, etc. By default, at power-up, the data pointer of the RTC chip is at the first byte i.e. D0. When microcontroller sends the clock for the communication, the RTC chip sends the 8 bytes one-by-one by incrementing the pointer, and at the end the pointer is back to the first byte. If communication is stopped by some means mid-way, then the pointer stays there mid-way after the last byte that was sent successfully, say for example D5. Now the next communication will start from D5 and then sends D6, D7, D0, D1, D2, D3, D4 bytes next, like a circular buffer. This behaviour is an important consideration in our application because the rocker switch is controller directly by the user.
[0031] User can toggle the switch anytime during the working of the controller which means that the port pin can be grounded at the time when RTC chip is sending the data. In this case the communication broken since the pin is grounded through the switch and the data pointer in the RTC chip is stuck midway. Next time when the switch is toggled and the timer mode is active, the order of the data bytes received would appear random to the controller because the controller does not know where the pointer was stuck. Also, random toggling of the switch can result in random byte data received by the microcontroller. Hence a decoding algorithm is implemented in the microcontroller to reliably update the time data based on the received bytes from the RTC-chip.
[0032] The decoding algorithm works as follows. Buffer-1 is updated first with the received bytes. Next time Buffer-2 is updated with the received bytes. Buffer-1 and Buffer-2 are compared. Only if all but one bytes in the two buffers are exactly the same and for the remaining byte if the data in Buffer-2 is equal to the data in Buffer-1 incremented by 1, then use the Buffer-2 data to update the Clock Time data with the index of the one different byte as ‘seconds’. Once the index of seconds is known, other indices are also known based on the circular nature of the data buffer. If the condition does not match, then Buffer-2 is copied to Buffer-1, and we wait for the next time-window. This method updates the real-time clock data reliably with the time division multiplexing of the data line with the user controller rocker switch which can be toggled intermittently at random.

ADVANTAGES OF THE INVENTION
[0033] The present invention provides a low-cost microcontroller-based motor controller with real-time clock based timer.
[0034] The present invention enables enable multiple functions to be performed using lesser number of pins without the need for additional hardware for multiplexing, hence saving cost and also having a compact design.