INT of PIC one-chip computer cuts off mentality of designing and programming

The microcontroller-based water level controller and motor protector manages the on and off states of the motor based on the water level in the overhead tank (OHT). It regulates the tank's water level through a microcontroller, thereby providing automatic protection...

Communication with the MCP3028 ADC chip is achieved through a straightforward serial interface that adheres to the SPI protocol. The PIC16F84 or PIC16F628 does not possess a hardware SPI peripheral. However, a software-implemented SPI protocol can facilitate communication with the...

Drive a small (3.6V, <1A) brushed motor bidirectionally with a PIC microcontroller (MCU). The available space is extremely limited, so a single 3.6V power supply will be used for both the motor and the PIC, with minimal drive circuitry required. There is no dedicated motor driver IC that operates at this low voltage, making a discrete H-bridge the most suitable drive arrangement. The NXP PMV30UN and PMV32UP have been identified as suitable N-type and P-type drive MOSFETs. Since both the PIC and the motor share the same power supply, it is questioned whether it is possible to eliminate the usual driving circuitry for an H-bridge and connect the transistors directly to the MCU pins. Potential pitfalls of this approach should also be considered. To design a bidirectional motor drive circuit using a PIC microcontroller and a discrete H-bridge configuration, the following considerations must be taken into account. The H-bridge consists of four MOSFETs arranged in a configuration that allows current to flow through the motor in either direction, enabling bidirectional control. The NXP PMV30UN and PMV32UP MOSFETs are suitable candidates due to their low on-resistance and capability to operate at the required 3.6V supply voltage. The connections between the PIC MCU and the MOSFETs should be made with consideration of the gate drive requirements. Directly connecting the MOSFET gates to the MCU pins can be feasible, but it is essential to ensure that the MCU can provide sufficient gate drive voltage to fully turn on the MOSFETs. A typical threshold voltage for these MOSFETs is around 1V, so the output high level from the PIC should exceed this threshold to ensure efficient operation. It is also critical to incorporate pull-down resistors on the gate pins to prevent the MOSFETs from floating when the MCU is in a high-impedance state. This will help avoid unintended motor activation. Additionally, using gate resistors can help dampen any oscillations and limit inrush current during switching, which could potentially damage the MOSFETs or the MCU. Another consideration is the back EMF generated by the motor when it is switched off or when changing direction. This can induce voltage spikes that may damage the MCU or the MOSFETs. To mitigate this risk, flyback diodes should be placed in parallel with each MOSFET to provide a path for the back EMF, ensuring safe operation of the circuit. Thermal management is also a critical aspect of the design. Although the MOSFETs are rated for low on-resistance, continuous operation near their current limits can lead to significant heat generation. Adequate heat dissipation measures, such as heat sinks or thermal pads, should be considered. In summary, while it is possible to connect the MOSFETs directly to the MCU pins, careful attention must be given to gate drive requirements, protection against back EMF, and thermal management to ensure reliable and efficient operation of the bidirectional motor drive circuit.

This programmer requires only a basic terminal program capable of uploading an ASCII PIC HEX file. It does not matter what operating system or computer (MAC, Win98, XP, Vista, DOS, Linux, etc.) is used to talk to it. All of...

This page is a work in progress. The board and source files will soon be available for building and programming to play custom songs. After assembling the board, communication with the programmer was verified, and both the LED and switch...

This program uses an 8 bit DAC along with a 16F84 PIC microcontroller to generate a keyed sine wave. The 16F84 uses an RC clock which can be varied (with a suitable potentiometer) to allow a variable frequency control for...

Twenty-five musical keys and 25 LEDs are provided to denote F to F" with half notes in between. Memory can store a played tune. There are ten preprogrammed tunes (each has an average of 55 notes) masked in the chip....

C1 is a charge pump capacitor. This works as a voltage doubler. When TxD is negative voltage, C1 is charged through D7 from GND. If TxD carries out turn-on, since it will become positive voltage, the voltage charged in C1...

The switch control system utilizes sensors to inform the microcontroller of the trains' positions on the layout. This ensures that only one train occupies the main line at any given time and that switches are correctly set for the train's...