LogicStart MegaWing

The LogicStart MegaWing provides everything needed to get started with VHDL and FPGA development on the Papilio with one convenient and easy to connect circuit board.

Learn VHDL with Mike Field's free book written specifically for the Papilio and LogicStart MegaWing. Step by step examples and full source code walks you through using all the peripherals on the LogicStart.

Dive into the exciting world of customizable Soft Processor's with the ZPUino. Custom peripheral's such as a ZX Spectrum compatible VGA adapter and classic audio chips are just a few of the exciting possibilities. The LogicStart gives you peripherals to experiment with!

Explore the VHDL source code of classic video games such as Pac-Man! The LogicStart's VGA output and Micro-Joystick allow all of the Papilio Arcade games to be synthesized.

Discover all the projects that work with the LogicStart MegaWing or contribute your own!

Specifications

  • 7 Segment Display - 4 Character
  • VGA Port - 3r,3g,2b VGA Output
  • Mono Audio Jack - 1/8" Jack, Low Pass Filter
  • Micro-Joystick - 5 directions
  • SPI ADC - 12-bit, 1Msps, 8 Channel
  • 8 LED's - User Feedback
  • 8 Slide Switches - User Input

Quicklinks


Demo Video


Peripherals

LogicStart 7 Segment Display

The 7 Segment Display provides 4 character displays with a dot between each character. It is great for displaying anything from high speed debugging data to a low speed alarm clock.

NameDirectionFunctionArduino PinPapilio Wing PinPapilio One PinPapilio Pro Pin
AOutputA Segment7A7, AL7P57P75
BOutputB Segment10A10, AH2P65P83
COutputC Segment5A5, AL5P40P66
DOutputD Segment6A6, AL6P53P67
EOutputE Segment3A3, AL3P33P58
FOutputF Segment4A4, AL4P35P61
GOutputG Segment9A9, AH1P62P81
DPOutputData Point Segment1A1, AL1P23P51
AN0OutputAN011A11, AH3P67P85
AN1OutputAN18A8, AH0P60P79
AN2OutputAN22A2, AL2P26P56
AN3OutputAN30A0, AL0P18P48


LogicStart VGA

The VGA section of the LogicStart MegaWing uses 8 resistors to implement 256 color depth. VGA video is analog in nature so there needs to be some way to vary the RGB (Red, Green, and Blue) signals between 0V and .7V. For each RGB signal the shade, or intensity, of the color is controlled by varying the voltage of the pin between 0 and .7V. The finer control you have over the voltage the more colors you can create. For the LogicStart MegaWing we are able to control 3 Red, 3 Green, and 2 Blue bits which allows us to generate 8 different voltage levels between 0 and .7V for Red and Green and 4 voltage levels for Blue. If we add all three colors together we have 8 bit video which gives us (2^8=256) the possibility of 256 colors.

The usual options for controlling voltage on a pin are to use a DAC, PWM, Delta-Sigma, or a resistor ladder. For the LogicStart MegaWing we wanted to use the lowest cost and easiest method for a hobbyist. PWM and Delta-Sigma were ruled out because we did not think we would be able to vary the voltage with these methods fast enough to keep up with the VGA timing requirements. A DAC would be a good solution but was more than we needed for our modest requirements. A resistor ladder fit the bill perfectly because it is very low cost and easy to implement. The resistor ladder is made up of 3r, 3g, 2b resistors that all connect, in common, to the VGA connector on one side and individually to a digital I/O pin on the other side. Each digital I/O pin is controlled by the VGA controller inside the FPGA. Each pin can be set to either 0 or 1 with a 1 causing the resistor to contribute its voltage to the final voltage level. The voltage can be stepped up from 0 to the desired output voltage which in this case is .7V.

NameDirectionFunctionArduino PinPapilio Wing PinPapilio One PinPapilio Pro Pin
Red0OutputRed Bit 023B7, BL7P61P78
Red1OutputRed Bit 124B8, BH0P58P74
Red2OutputRed Bit 225B9, BH1P54P95
Green0OutputGreen Bit 020B4, BL4P68P84
Green1OutputGreen Bit 121B5, BL5P66P82
Green2OutputGreen Bit 222B6, BL6P63P80
Blue0OutputBlue Bit 018B2, BL2P78P92
Blue1OutputBlue Bit 119B3, BL3P71P87
VSyncOutputVertical Sync16B0, BL0P85P99
HSyncOutputHorizontal Sync17B1, BL1P83P97


LogicStart Sound

The sound section implements a 1/8th inch mono jack with a low pass filter. Projects simply implement a Delta-Sigma DAC as outlined in Xilinx App Note 154. A Delta-Sigma DAC allows high quality audio to be implemented with a minimum amount of physical hardware required. The high speed of the FPGA clock allows the FPGA to do the heavy lifting of the Digital to Analog conversion.

NameDirectionFunctionArduino PinPapilio Wing PinPapilio One PinPapilio Pro Pin
AudioOutputAudio Output26B10, BH2P41P62


LogicStart Micro-Joystick

The LogicStart MegaWing has a 5 direction micro-joystick that can be used for user input or video games!

NameDirectionFunctionArduino PinPapilio Wing PinPapilio One PinPapilio Pro Pin
SelectInputPress Joystick In31B15, BH7P22P47
UpInputPress Joystick Up30B14, BH6P25P50
DownInputPress Joystick Down29B13, BH5P32P55
LeftInputPress Joystick Left28B12, BH4P34P57
RightInputPress Joystick Right27B11, BH3P36P59


LogicStart SPI ADC

The SPI ADC allows pots, pot slides, temp sensors, and many more analog devices to be connected, up to 8 devices at once.

The SPI ADC uses the ADC128S102 chip from National.

NameDirectionFunctionArduino PinPapilio Wing PinPapilio One PinPapilio Pro Pin
CLKOutputClock15A15, AH7P86P100
MOSIOutputMaster Out Slave In14A14, AH6P84P98
MISOInputMaster In Slave Out13A13, AH5P79P93
CSOutputChip Select (Active Low)12A12, AH4P70P88


LogicStart LEDís and Switches

The LogicStart MegaWing provides 8 LEDís and 8 Slide Switches.


NameDirectionFunctionArduino PinPapilio Wing PinPapilio One PinPapilio Pro Pin
Led0OutputLed 040C8, CH0P5P123
Led1OutputLed 141C9, CH1P9P124
Led2OutputLed 242C10, CH2P10P126
Led3OutputLed 343C11, CH3P11P127
Led4OutputLed 444C12, CH4P12P131
Led5OutputLed 545C13, CH5P15P132
Led6OutputLed 646C14, CH6P16P133
Led7OutputLed 747C15, CH7P17P134
SW0InputSwitch 032C0, CL0P91P114
SW1InputSwitch 133C1, CL1P92P115
SW2InputSwitch 234C2, CL2P94P116
SW3InputSwitch 335C3, CL3P95P117
SW4InputSwitch 436C4, CL4P98P118
SW5InputSwitch 537C5, CL5P2P119
SW6InputSwitch 638C6, CL6P3P120
SW7InputSwitch 739C7, CL7P4P121


Images

LogicStart MegaWing High Resolution Image

Click the image to load a High Resolution image of the LogicStart MegaWing

LogicStart MegaWing Schematic

Click the image to load a PDF version of the LogicStart MegaWing Schematic

Assembly View

Click the image for a full size view of the boards part layout.


  

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