Microchip Technology Inc.

Scott Ellison

Richard L Hull

Scott Raymond Fink

Gregory C Bingham

Rodney J Drake

Russell E Cooper

David M Susak

James B Nolan

Brian E Boles

Paul H Hofhine

An Integrated Circuit (IC) package is disclosed comprising an IC chip with a microcontroller therein having an n-bit data bus, and up to n pins electrically coupled to the microcontroller. The IC package also includes a control register coupled to the microcontroller for receiving enable and disable signals from the microcontroller. One or more of the pins have one or more functional block associated thereto. Each functional block defines a specified function for its corresponding pin. Thus, each pin having a plurality of corresponding functional blocks has a number of potential functions equal to the number of corresponding functional blocks. The specific function for a given pin is selected by the enable signal from the control register which selects the appropriate functional block upon appropriate command from the microcontroller. By using pins with multiple functions, the instant invention permits an n-bit architecture microcontroller to use less than or equal to n pins.

Integrated circuit (IC) package with a microcontroller having an n-bit bus and up to n-pins coupled to the microcontroller

An Integrated Circuit (IC) package is disclosed comprising an IC chip with a microcontroller therein having an n-bit data bus, and up to n pins electrically coupled to the microcontroller. The IC package also includes a control register coupled to the microcontroller for receiving enable and disable signals from the microcontroller. One or more of the pins have one or more functional block associated thereto. Each functional block defines a specified function for its corresponding pin. Thus, each pin having a plurality of corresponding functional blocks has a number of potential functions equal to the number of corresponding functional blocks. The specific function for a given pin is selected by the enable signal from the control register which selects the appropriate functional block appropriate command from the microcontroller. By using pins with multiple functions, the instant invention permits an n-bit architecture microcontroller to use less than or equal to n pins.

Method and apparatus for controlling the updating of a random access memory (RAM) that stores data for coding the activation of segments of one or more alphanmeric characters of a liquid crystal display (LCD), to maintain substantially a direct current (DC) voltage value of zero across transparent conductive plates of the LCD, is performed or provided in a microcontroller having internal LCD control capabilities. A type B waveform is employed for activating the LCD, the waveform being of a type in which data is transmitted over two frames, the data in the second frame of which is the inverse of data in the first frame thereof to maintain an average DC voltage value over each two-frame portion of the waveform at substantially zero volt. The RAM is allowed to be written to for updating the data therein only after completion of an entire two-frame portion of the waveform and before commencement of a new two-frame portion, to avoid a non-zero average DC voltage across the LCD glass during a two-frame portion. An error bit is set whenever an attempt is made to write to the RAM at times other than between the end of a two-frame portion and the commencement of a new two-frame portion. A response to the error bit is made by returning to the write step that prompted it, to determine whether all of the data intended to be written has been stored in the RAM.

Microcontroller with LCD control over updating of RAM-stored data

A free-running microcontroller (i.e., one without any reset signal) is shown with special mode enable detect logic for placing the microcontroller into the test or special operations mode, without the benefit of a dedicated pin for such purposes. Rather, the instant invention implements the methodology of first applying a test voltage to indicate to the free-running microcontroller that the test mode is to be entered. Since the device has no reset signal to interrupt normal operation once it has begun, the test voltage is applied before the power supply V.sub.DD to ensure that the device enters test mode before it can enter normal operation.

Microcontroller having special mode enable detection circuitry and a

A precision oscillator circuit having a wide adjustable operating frequency range and an adjustable duty cycle. The precision oscillator use a window comparator circuit for monitoring a voltage of a capacitive element. The window comparator circuit has a first operating voltage edge and a second operating voltage edge wherein the first operating voltage edge latches an output signal of the window comparator circuit at one level when the voltage of the capacitive element is greater than the first operating voltage edge. The second operating voltage edge brings the output signal of the window comparator circuit back to an initial level when the voltage of the capacitive element is greater than the second operating voltage edge. A precision current reference source is coupled to the capacitive element and to the window comparator circuit. The precision current reference is used for generating currents which are insensitive to temperature, supply voltage, and process variations. The currents are used for charging and discharging the capacitive element. The currents are adjustable in order to vary an amount of time it takes to charge and discharge the capacitive element. This allows for the altering of the frequency as well as the duty cycle of the output signal of the window comparator circuit.

IC (current-capacitor) precision oscillator having frequency and duty

Apparatus for providing multiple of discrete voltage levels to drive a liquid crystal display (LCD) from an LCD module on board a microcontroller chip includes a charge pump with a switched-capacitor that develops the discrete voltages as multiples of the value of a base voltage that remains substantially without change irrespective of change in the supply voltage. A switched-capacitor charging circuit selectively charges a capacitor to produce successive additive charges individually retrievable from the capacitor. An LCD drive selectively transmits the discrete voltage levels to activate the LCD according to status of an external system under the control of the microcontroller. Voltage losses that may occur during the switched-capacitor charging are compensated to maintain the levels of the discrete voltages free of decay. Compensation is achieved by overcharging the capacitor by an amount substantially equivalent to the amount of voltage loss on the capacitor, using active feedback obtained from monitoring the charge on the capacitor.

Microcontroller chip with integrated LCD control module and switched

An Integrated Circuit (IC) package is disclosed comprising an IC chip with a microcontroller therein having an n-bit data bus, and up to n pins electrically coupled to the microcontroller. The IC package also includes a control register coupled to the microcontroller for receiving enable and disable signals from the microcontroller. One or more of the pins have one or more functional block associated thereto. Each functional block defines a specified function for its corresponding pin. Thus, each pin having a plurality of corresponding functional blocks has a number of potential functions equal to the number of corresponding functional blocks. The specific function for a given pin is selected by the enable signal from the control register which selects the appropriate functional block upon appropriate command from the microcontroller. BY using pins with multiple functions, the instant invention permits an n-bit architecture microcontroller to use less than or equal to n pins.

Microcontroller having an n-bit data bus width with less than n I/O pins

An accurate RC oscillator circuit located within a microcontroller chip for generating a signal of a predetermined frequency that accurately oscillates between two precise voltage levels, i.e., a low voltage (VL) and a high voltage (VH) is disclosed. The oscillator circuit uses first and second comparators having their outputs respectively coupled to set and reset inputs of a flip flop. The output of the flip flop is coupled to a series RC network for controlling the charging and discharging of the voltage across a capacitor of the RC network. The interconnection of the series RC network is coupled to an input of both the first and second comparators. The other input of the first comparator is coupled to a circuit for applying a modified high threshold version (VH') of the high voltage such that the signal generated by the oscillator circuit does not exceed the precise high voltage (VH). Similarly, the other input of the second comparator is coupled to a circuit for applying a modified low threshold version (VL') of the low voltage such that the signal generated by the oscillator circuit does not fall below that precise low voltage (VL). Additionally, means are provided to select different input voltages for the low voltage (VL) such that the desired output frequency of the oscillator may be adjusted to accurately oscillate between the high voltage (VH) and the selected low voltage (VL).

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Chandler, AZ, United States of America

Scott Ellison