DEV-1 HamStack Development Board

Transcription

1 Sierra Radio Systems DEV-1 HamStack Development Board Reference Manual Version 1.0

2 Contents Introduction Hardware Compiler overview Program structure Code examples Sample projects For more information, go to the Sierra Radio Systems web site at or

3 DEV-1 Board - Parts Placement Diagram 6 pin DIN Do not install

4 CPU Board Pin Assignments & Parts Placement Diagram The CPU board is powered by the DEV-1 board so there is no need to plug a power supply into the DC power jack Remove jumper JP1 when using the CPU board plugged into the DEV-1 board. Plug PICKit2 compatible programmer into J9 or into J7 on the DEV-1 board. User A - not used User B - not used RS232 Rx RS232 Tx RE2 Encoder button RA4 Button 4 RC1 PS2 keyboard data RC2 PWM Tone out Reset 3.3v - Not used 5.0v from DEV-1 Ground Ground External voltage in RA0 Analog input RA1 Button 1 RA2 Button 2 RA3 Button 3 RE0 Encoder A RE1 Encoder B RC0 / Status LED Programming pin PData Programming pin PClk RB4 - Relay RB3 LED 4 RB2 LED 3 RB1 LED 2 RB0 LED 1 Bias not used Ground RC3 I2C Clock not used RC5 I2C Data not used RC4 Not used RA5 PS2 keyboard clk RD7 OneWire bus RD6 Not used RD5 LCD E pin RD4 LCD RW pin RD3 LCD D7 RD2 LCD D6 RD1 LCD D5 RD0 LCD D4 RC6 UART Serial Tx RC7 UART Serial Rx Reset Button This button will cause the CPU to reset. J7 RS232 Pin 1 Tx Pin 2 Rx Pin 3 - Ground Mode Button Connected to RA4, the mode button is used by some applications and is wired to Button 4 on the DEV-1 board. Status LED Connected to CPU pin C0 and is typically used to indicate program status. User programmable. Pwr LED Indicates power is present on the CPU board. Some CPU pins are not used with the DEV-1 board including RC3, RC4, RC5, and RD6. They are not pre-wired to any devices on the DEV-1 board. These pins are available for the user to use for custom applications. Adding a stacking board on top of the CPU board provides easy access these and all other pins. RC3 and RC5 are the I2C bus which is very convenient for connection to all kinds of devices including memories, sensors, IO expanders, etc.

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6 Audio Amplifier CPU pin RC2 PWM output from CPU RC2 +5V The audio amplifier takes the output of the CPU s pin RC2, which has a hardware Pulse Width Modulator output, and will shape the wave into a sine wave using the RC filter R8, R9, C11, C13. The raw filtered signal is available at the 3.5mm jack J5. The audio then passes into an LM386 audio amplifier and to the local speaker. The pot R21 is used to set the audio level. If fixed levels are needed, the user resistors R11 and R12 can be installed instead of the pot. Note: components in the feedback loop, R13 and C10, are optional depending on the gain desired. The default configuration includes C10 installed with a 10uf capacitor and a jumper wire in the R13 position.

7 Pot External Analog Input +5v Use jumper JU1 to select the analog input. Pot connects the built in potentiometer. External allows an external voltage input. The analog to digital converter (ADC) input can measure from 0 to 5 VDC. This value is reported as a number between 0 and When using the external voltage input on connector P6, the input voltage goes through a simple voltage divider using a 10k series resistor and a 2.2k resistor to ground. This provides a usable range of VDC. The in this case, each unit from 0 to 1023 represents a resolution of volts. GND RA0 OneWire Temperature Probe +5v JU3 is a 3 pin connector to provide a connection to an external OneWire sensor. +5v OneWire Ground RD7 CPU pin RD7 is used as the data pin for OneWire sensor devices. Typically used for sensors like digital temperature devices, the OneWire interface connector J3 provides +5v, data and ground. There is also a TO-92 footprint on the PCB that can be used to install an optional DS18B20 temperature chip.

8 A B Digital Inputs and Buttons +5V +5v RA1 RA2 RA3 RA4 RE0 RE1 RE2 RE0 Encoder A RE1 Encoder B RE2 Encoder push button GND The rotary encoder has two outputs which creates wave forms 90 degrees out of phase. These signals are decoded to produce a count up pulse or a count down pulse. For example, if the last value was 00 and the current value is 01, the device has moved one half step in the clockwise direction.

9 LCD and LED Displays +5V +5V RD5 RD4 RD3 RD2 RD1 RD0 This LCD display uses the industry standard 4 bit Hitachi interface. The CPU uses 6 wires, 4 for data and 2 for control. Pot R17 is used to set the contrast on the display. An extra connector, J6 is wired in parallel with the built-in LCD display if an external display is going to be used. Normally J6 is not used. RB3 RB2 RB1 RB0 RB0.. RB3 are wired up to 4 LEDs. When the CPU pin is set high, +5v, the LED will be turned on. Jumper block JU2 is provided to allow the user to disconnect any of the CPU pins RB0..RB3 from the LEDs and free up the CPU pins to be used for another purpose.

10 External Connections RA5 RC1 PS2 Computer Keyboard This connection provides a convenient way to take user input into an application running on the HamStack CPU. The PS2 keyboard requires the hs_keyboard.bas library to be included in your source code. RC6 RC7 RS232 Serial Port The CPU chips s main serial UART is connected to a TTL to RS232 level shifter chip (MAX232) located on the CPU board. Those RS232 signals are routed through the inter-board header connectors to the DEV-1 board then to J2, a female DB9 serial data connector. Pin 2 Transmit data out of the board. Pin 3 Receive data input to the board. Pin 5 Ground RB4 SPDT Relay The board includes a single pole double throw (SPDT) relay. The relay control signal comes from CPU pin RB4. When pin RB4 is high, +5v, it will turn on Q1 pulling the collector of the transistor to ground. This will complete the circuit allowing current to flow through the relay coil and actuating the relay. LED D8 will indicate when the relay is turned on. Diode D5 is used to eliminate counter EMF. It s the voltage produced by the interaction of current in the coil of the electromagnet its magnetic field, when one, or both, is changing.

11 Power Supply

12 Circuit Examples Blink an LED Description In this example we will show how to turn an LED on and off. The DEV-1 board has 4 user programmable LED labeled LED 1 through LED 4. They are also assigned reference designators on the schematic as diodes D1, D2, D3 and D4 respectively. The Anode, or positive side, of each LED is connected to a pin of the CPU chip. We will use port B, pins 0, 1, 2, 3 to control the four LEDs. The Cathode or negative side of each LED is connected through a 270 ohm current limiting resistor to ground. You may notice a fifth LED, D7, which is connected to the +5v power rail. This is the board s power indicator LED and is shown in the schematic for completeness. The program examples that follow will show how to blink the LEDs. Simply put, when you set the CPU output pin to high or 1 state (+5v), the LED will light up. When you set the output pin to a low or 0 state (ground), the LED will be off. Jumper block JU2 is used to enable the electrical path from the CPU to each LED. This jumper block is provided to allow the developer the option to disconnect any of the four pins RB0, RB1, RB2, RB3 from each LED and allow you to use any of these CPU pins for another purpose. For this tutorial, all four jumpers should be installed. TIP! Don t underestimate the value of LED indicators. They can be very useful as an aid to debugging your code. You can use LED to indicate when you enter a branch of you program, show how fast an operation is taking place or simply let you know an internal variable has been set to 1 or 0. Think of them as a very simple print statement. Circuit

13 Circuit Examples Blink an LED Basic Language '--- Blink the LED Device = 18F4620 Clock = 40 Config osc = hspll '--- Set pin direction TRISB.0 = 0 '--- Begin main program master_loop: High (PORTB.0) 'LED on DelayMS (500) 'Wait Low (PORTB.0) 'LED off DelayMS (500) 'Wait GoTo master_loop Comments In this program we create a simple loop which will blink the LED every second. The program also shows the minimum set of commands necessary for any program as follows Device = 18F4620 tells the compiler which chip we will be using. Clock = 40 tells the compiler we will be using a 40 MHz clock frequency. Config osc = hspll Tells the compiler to configure the chip so that it takes the physical clock crystal (10 MHz) and puts the internal oscillator circuit in High Speed PLL mode which multiplies the hardware crystal frequency 4x resulting in our 40 MHz frequency of operation. TRISB.0 = 0 Sets CPU pin named port B0 to be an output (0, zero) Then comes the master loop. In this example we are using a simple goto command to create the loop. master_loop is a label which will be jumped to at the end of the loop using the goto command. High (portb.0) Sets output pin RB0 to +5v or logic 1 DelayMS(500) Waits 500 miliseconds Low (portb.0) Sets output pin RB0 to ground or logic 0 DelayMS(500) Waits 500 miliseconds GoTo master_loop Sends the program to label master_loop C Language