Category Archives: Parallax Propeller

IEE Flip VFD Working! Test code coming soon.

Today I wrote some code to get the IEE Flip VFD working. It has a fairly simple protocol and only took a bit of tweaking to get it working. I wrote the demo code for my Prop Dev Stick and will be uploading the SPIN code later once I finish the feature set.

After this I will write some C code for the MSP430 LaunchPad and get that working. The screen supports a serial input mode which saves 8 I/O pins but requires more timing. I will try to get that working as well.

IEE FLIP Alphanumeric Display Works!

I picked up some of these really neat VFD alphanumeric displays at a surplus shop while at Maker Faire. After acquiring the datasheet from the manufacture, I decided to test them with the built in test mode. I have already started writing the code to run the display and will be posting the code and datasheet when it is done.

WS2801 – 3 Channel PWM

The WS2801 is a 3-channel constant current LED drivers that is designed for controlling chains of RGB LEDs. The IC is controlled by a 2-wire serial control scheme that allows multiple WS2801 to be chained together. You can find the WS2801 in the link below. This demo code basically shifts out 24 bits (8bits per color) using a 2-wire protocol. This code only works for one WS2801. There is a object designed for multiple WS2801 already in the propeller OBEX. That design uses too many resources for use on my pinball machine so I wrote this to use as little resources as possible (no new cog).

The idea would be to have the WS2801 PWM a set of mosfets which would in turn be connected to the string of LEDs. This way you could light up a bunch of RGB LEDs without allot of CPU time taken from the Propeller. The Propeller only has to mess with the WS2801 when it needs to change the PWM signals.

Where to buy the WS2801.
Demo Driver

LDMD 16×16 Propeller Comm Test

Just finished the DMD (Dot Matrix Display) test for RESET_VECTOR. Since the Propeller is to slow to do the matrixing I am going to use a FPGA to do it. The propeller will send the data over a serial connection into a frame buffer on the FPGA. When all the data is on the FPGA the FPGA will update its matrixing buffer.

I have the Propeller to FPGA communication protocol written and tested as well. The Propeller loads the Data off the SD card and sends it serially to the FPGA.

Propeller Code
FPGA Code
Block Diagram of the Dot Matrix.