Another day another update on REV 0 of Tommy. Nearing the end. Just have to route the connections for the DMD port and the I/O connection for add on boards.
Just started my new DMD. This will be a 128×32 RGB DMD with a 4mm pitch. Total display size will be around 5″x20″ so it is almost twice as large as a normal DMD but it will be in color. I ordered a single 32×32 matrix (seen above) and took some sample code from adafruit’s website to get it working.
Since the proof of concept is working I will expand it to the 128×32 by adding 3 more modules and running the display off of a Ti Stellaris LaunchPad. The Stellaris LaunchPad runs at 80Mhz so it will be plenty fast enough to do the matrixing. It will have an onboard SD Card so it can pull the images off of it. The main controller of the pinball machine will use an I2C bus to tell the LaunchPad which image to display.
To add more functionality to the Propeller an ATMega168 was added to the design. The Propeller communicates via I2C (on the same bus as the EEPROMS) to the ATMega168. The ATMega168′s function is to provide dedicated servo control and analog input for the propeller. Since servos have to constantly PWM controlled the Propeller has to dedicated an entire cog to just maintain servos. Using the ATMega168 to off load this tasks frees up lot of resources for the Propeller which will allow for better animations and smoother kernel cycles.
I fixed the EEPROM addressing issue. Since the EEPROMs are addressed via I2C protocol you have to set there addresses via the pins A0, A1, A2. Previously I had these all to VSS or GND which would mean all there addresses where 000.
Added the SD Card to the Parallax Propeller to store audio files. Took longer then expected to make the footprint and get the part correct in eagle.
Power will come into the board via 4-Pin Molex connectors much like on a PC power supply.
Currently have TLC5940 16 channel LED drivers on the board but these will be changed to WS2803 Chips as they use 3 less I/O lines (5 vs 2). These will be used exclusively for RGB LED lighting. I am planning on being able to hook up 18 RGB LEDs to the board.
For those that don’t know, Tommy is the code name for a propeller based pinball platform. It will be an all in one system that is designed to be modular and easy to use.
Ben has been working on the code and is getting the test hardware going.
He has most of the system working now. In the picture, Ben is working on the switch matrix and DMD driver part of the code as there where conflicts earlier.
This weekend I will be starting the PCB design. I should have rough version of the prototype PCB drawn up by Monday.