AVR Intermediate Development Board. Product Manual. Contents. 1) Overview 2) Features 3) Using the board 4) Troubleshooting and getting help

Transcription

1 AVR Intermediate Development Board Product Manual Contents 1) Overview 2) Features 3) Using the board 4) Troubleshooting and getting help

2 1. Overview 2. Features The board is built on a high quality FR-4(1.6 mm) board with a green solder mask and a clear and legible white legend Onboard Serial and USB(optional) interface options for easy connection to external devices and computers Onboard 16x2 LCD support Onboard rectifier enables the board to be used with AC and DC input powers and provides reverse polarity protection Onboard 5V regulator with heatsink for best performance Power Status LED(Green) along with 4 x general purpose LEDs and 4 x General purpose switches AVCC pin connected to 5V through inductor for accurate ADC conversions Onboard quartz crystal 16 MHz oscillator circuit Port extensions for all ports Onboard power bus for Vin, Gnd and 5V lines Comes with a detailed product manual and an excellent after sales support

3 3. Using the board The AVR Development Board with LCD consists of everything needed to get started with AVR programming easily. It sports an onboard power regulator, crystal oscillator, reset circuit, Serial RS232 and USB connections for easy connections to external devices and computers, port extensions for all ports, etc. Power Supply The board consists of a DC Jack to which the input power has to be applied. The board can work on voltages within the range of 7-15V. The board can accept both DC and AC voltages and provides reverse polarity protection. This power input is first rectified and then regulated to output a constant 5V. The input voltage, Gnd (-ve), and 5V are provided at the Power Bus and can be used to power external circuits. The onboard 5V regulator can provide a maximum of 1A of current. An onboard power switch controls the power to the board. Alternatively, the board can also be powered of the 5V supply from the USB port when connected to a computer through the USB port on the board. The USB port can provide a maximum current of 100 ma. The boards onboard peripherals consume a little of this current and leave the rest unused. Hence, only a part of this current is left for the user. Please make sure you do not draw more than 50 ma of current when powered of the USB port, else you may damage your USB port. An onboard power selector (labeled Power Input Selector in the Overview section) can be used to select the power supply to the board between the USB port and the External Power Supply. Putting the jumper between one side of the outer pins selects External Power Input and putting it on the other selects USB power. Once you have the board powered on you should see the green power status LED light up. Serial and USB Connections The board provides an industry standard RS232 interface circuit which can be used to connect the board to an external device with serial interface or to a computer through a serial cable. The board also sports a USB to Serial Converter which can be used to do serial interfacing between the microcontroller and a computer. The board uses the CP2102 IC from Silicon Laboratories for handling the USB to Serial Conversion. The first time you connect the board to a computer, you will be required to install drivers for the board. Please follow our CP2102 Driver Installation Tutorial to install the drivers. You may find the tutorial under the Resources section of our website ( ). A copy of the installation guide is also provided on the product CD.

4 Once the drivers are installed you will have to find out the COM port to which board is connected to. To do this right click on the My Computer icon, click on Properties and select the Hardware tab in the dialog box that appears. Under the Hardware tab, click on Device Manager. In the Device Manager Dialog box, open the list Ports (COM & LPT). Note down the COM port number which appears beside the device name Silicon Labs CP210x USB to UART Bridge. You will need the COM port number to tell the computer to which port the board is connected during serial programming and communication. LCD Display The board supports a standard 16X2 LCD Display. The LCD can be plugged onto the board through the 16 pin female connector. The LCD pins are wired to PORT2 and can be controlled through a 4 bit interface. The connections between the LCD and the microcontroller are as follows LCD RS -> PB0 LCD RW -> PB1 LCD EN -> PB2 LCD D4-D7 -> PB4 PB7 The onboard potentiometer controls the contrast of the LCD. Adjust it until the characters on the LCD appear clearly. The characters on the LCD will be faint and not visible if the contrast is not set correctly. Crystal Oscillator The board by default comes with an onboard crystal oscillator circuit consisting of a 16 MHz quartz crystal and the required capacitors. If you would like to use the microcontroller on a different speed, you may replace this crystal with the crystal of the required frequency. Make sure you replace the capacitors also to match the crystal you use. Please refer the datasheet of the microcontroller for more information. General Purpose LEDs The board has 4 x general purpose LEDs which can be switched on and off by the microcontroller. The LEDs are connected to Vcc through a suitable resistor as shown in the circuit. To control the status of the LED, you will first have to set the LED pin as output. To switch on the LED you will have to set the LED pin as low and to switch it off set it as high. LED LED 1 LED 2 LED 3 LED 4 Connected to Pin PD4 PD5 PD6 PD7

5 General Purpose Switch The onboard switches can be used to send input signals to the microcontroller. Every time a switch is pressed a low signal appears at its pin. Switch Switch 1 Switch 2 Switch 3 Switch 4 Connected to Pin PC6 PC7 PC1 PC0 Note: A few pins of PORTC are also used for JTAG applications. Since, the microcontroller (Atmega16 and Atmega32)comes with the JTAG option enabled by default, the pins will be unusable for normal I/O. To use the pins for I/O operations, you will have to disable the JTAG option, by setting the right fuses. Please refer the microcontroller datasheet for more details. ADC Reference The positive reference for the ADC(AREF) can be provided to the pin named ARef on the board. Please read datasheet for the respective device to know more about AREF and its use. The general purpose potentiometer can be used to provide AREF by putting a jumper between the AREF and the potentiometer output. Reset Button The board provides a reset switch which is connected such that it resets the microcontroller every time it is pressed. Upon reset, all registers are set to their default value and the program is executed from the beginning. Port Extentions All IO pins are brought out to male header pins for easy connections with external circuits. Two parallel empty holes are also provided to each IO pin, which can be used to solder in wires directly and provide easy expansion. The pin name and any dual functions of each pin are also printed on the board next to each pin for easy prototyping.