Upduino v2 examples with icestorm

Several demos showing how to use the icestorm toolchain with the Upduino (ice40 UltraPlus 5k) FPGA dev board.

Demo	Description
blink	Flash the RED LED in a pulse-pulse, pulse-pulse pattern
pulse	Smoothly ramp the RGB LED through a color change pattern
serial	Print a repeating message on the serial port at 3 Mbs
seral-echo	Read from the serial port, echo it back at 3 Mbs
spram-demo	Read from the serial port, buffer in SPRAM, echo it slowly

To flash them, run sudo make blink.flash. You will probably need to be root to flash the board and restore the /dev/ttyUSB0 device driver after iceprog switches it into SIO mode.

Schematics and pinout

Schematics for the upduino: https://github.com/gtjennings1/UPDuino_v2_0

Note that the upduino_v2.pcf file disagrees with the serial port in the pinout and schematic. The pins were determined through experimentation and seem to work (and the ones in the pinout do not).

UltraPlus 5K overview

Overview: http://www.latticesemi.com/Products/FPGAandCPLD/iCE40UltraPlus

Datasheet: http://www.latticesemi.com/-/media/LatticeSemi/Documents/DataSheets/iCE/iCE40-UltraPlus-Family-Data-Sheet.ashx