BlueBird

Since my first introduction to FPGA's during my freshmen year at TU/e, I've been looking for a way to own my own FPGA development board. After looking at several commercial boards from company's like Terasic and KNJN. But all these boards where to expensive and most mist vital features. Therefor I decived to design my own low budged high feature FPGA development bord, named: BlueBird.

After much consideration it was decided that bluebird board should have features for a price of at most $75.

* Altera Cyclone I 1C6 FPGA device
* Altera Serial Configuration device
* 16 Mbit of dataflash
* microSD card socket
* 6 pushbutton switches
* 8 toggle switches
* 16 red user LEDs
* 4 red 7 segment displays
* 50MHz oscillator
* R2R 6-bits VGA DAC with VGA-out connector
* USB to UART controller with USB B female connector
* PS/2 mouse/keyboard connector
* IrDA receiver (36kHz)
* Two 20 pins expansion headers
* JTAG and AS connector

Some features will be explained in more detail below .

The choice for the Altera Cyclone was made for it's low price and feature richness. Compaired to other FPGA's in a TQFP-144 package offered by digikey, only the Cyclone II has an beter LE's to price ratio. The EP1C6 was favored above the EP2C5 for the 1300 additional LE's and 5 additional IO's .
Although the EP2C5 also had an strong case with an addition 27,648 bits of RAM (26 vs 20 M4K RAM bloks) and 13 internal 18×18 multipliers . Both have 2 internal PLL's.

The config prom give the board the abbiltiy to make the design non-volitale. Although not vital for a development board, one could think of situation where it could be handy to store the design while no power is supplied to the board.

The main reason for giving the BlueBird board a 15-pins HD¹⁾ D-SUB connector is so that it can be used as a simple gaming platform. The EP1C6 makes it ideally used for running games as teteris and pong.
The synchronization signals are directly generated by the FPGA. The analog Red, Green and Blue signals are generated using and 2-bit R2R DAC for each color. All signals are buffered with an Analog Devices ADA4851 high speeds video buffer, giving it the capabilty of displaying 64 color at a resolution of 1024×786 (60Hz refresh rate²⁾).

^{Figure 1 - Color pallet.}

For more information about the VGA protocol, have a look here

You can download the schematic for the Bluebird board at: bluebird.pdf (191 kB).
The board design and layout is available at: bluebird.zip (775 kB).
Note that the bottom layers are mirrored!
The BOM (Bill of Materials) is available at: bluebird.bom (16 kB).

The board has the following specs:

102x82mm in size
2 layers

128 TH pads
605 SMT pads
277 via's
10 mounting holes

12 different drill sizes (smallest: 0.35mm, largest: 3mm)
smallest wire: 10mil
smallest clearence: 10mil
smallest pitch: 0.5mm