Team 8:
Nate Gimple
Steven Tighe
Amit Halevi
Noah Husek
Project Summary
 LED Cube!
 RGB LEDs
 512 LEDs, 64 microcontrollers
 Massively networked (64 microcontrollers
intercommunicating)
 Uses the Atmel ATxmega64A1
 Uses the Altera Nios II softcore
Noah
Project Status
 Prototype boards ordered
 Almost all components acquired
 Microcontroller intercommunication via UART
 Currently slightly under budget!
 Familiarization with Nios II IDE
 Familiarization with Xmega IDE
Noah
Hierarchy / block diagram
user
input
Nios II
I2C
super
node 0
node 0
(LED)
Amit
node 1
super
node 1
…
module 0
…
node 7
super
node 7
sensor
input
super
node 8
…
super
node 63
Addressing
 Fractal
 1st digit = top or bottom
 2nd digit = back or front
 3rd digit = left or right
 000 011 100
 mod sup node
 This address indicates:



010
110
001
011
100
Top, back, left module
Top, forward, right supernode
Bottom, back, left node
 3 bits of address:
 Eases writing generic code
Amit
000
111
101
Communication Scheme
Nios II
Supernode
Supernode
Supernode
Supernode
Supernode
Supernode
I2C
UART
Amit
ATxmega64A1
 32 MHz
 64 kB Flash memory
 8 USARTs
 4 I 2C
 SPI
 Integral timers
 2 12 bit ADCs
 128 bit crypto engine!
 Donated by Atmel
Amit
Altera + Nios II
 Master controller FPGA
 Processor implemented with logic synthesis
 Softcore capable of running C
 I2C will be implemented in hardware, with use of
extension headers on board
Noah
TI TLC5947 LED Driver
 24 channels
 12 bit PWM
 Serial input
 Programmable constant current sink
 Up to 33 V on each channel
 QFN 32
 Considered discrete MOSFET drivers
 Not enough ports on chip
 Footprint => 2 layer
 Donated by TI
Noah
 RGB LED
 4 lead, common anode
 Diffused epoxy
 5 mm diameter
 20 mA
 Using leads as structural member
 Surprisingly expensive to buy 500
Noah
PCBs
 3 kinds of PCBs
 Supernode 1.7” x 1.7”
 Row 0.3” x 2.0”
 Column 0.4” x 3.9”
 Need 64, 64, 96 respectively
 All 2 layer
 Supernode was originally 4 layer
 Changed to 2-layer for cost
 Use of QFN package LED driver allowed this
Steven
Supernodes: Schematic 1
Steven
Supernodes: Schematic 2
Steven
Supernodes: Layout
Steven
Rows and Columns
Steven
Power Supply
 Computer power supplies
 Highly regulated voltage
 5 V, 3.3 V, 12 V available => 5 V used
 Internal soft start

Nate
inrush current is
not a problem
BOM and Budget
Item
Part #
LED
microcontroller ATxmega64A1
LDO
ADP3338
LED driver
TLC5947
i2c buffer
LTC4300A-1CMS8#PBF-ND
NTC thermistor 495-2116-1-ND
photocell
PDV-P9001-ND
microphones
BOB-08669
op amp
AD8052
capacitor
TPSE337
capacitor
capacitor
resistor
741X043103JPCT-ND
resistor
P2.55KHCT-ND
connectors
WM2701-ND
connectors
SAM1034-50-ND
power supply
solder paste
KE1507-ND
Kapton film
2271K2
PCBs
Total
Nate
value
RGB
3.3V
10 kΩ
330 µF
4.7 µF
0.1 µF
10 kΩ
2.55 kΩ
3 pin
100 pin
12" x 12"
-
Quantity
600
64
64
64
1
100
64
4
64
64
320
640
100
200
96
4
2
1
2
240
Cost ($) Ext. Cost ($)
Description
0.3280
196.80
4 pin RGB common anode 5mm diffused LED
0.0000
0.00
Free! Donation from Atmel.
0.0000
0.00
3.3V LDO
0.0000
0.00
Free! 24 channel PWM LED driver from TI
3.5000
3.50
i2c hot-swappable driver/buffer
0.2470
24.70
temperature sensor
1.0200
65.28
light sensor
7.9500
31.80
sound sensor
0.0000
0.00
dual op amp to buffer sensors
0.0000
0.00
tantalum cap for 5V
0.0000
0.00
ceramic decoupling caps for 3.3V and 5V (LEDs)
0.0000
0.00
ceramic decoupling caps for µC
0.0110
1.10
pull-up for i2c
0.02255
4.51
sets IREF constant current
0.0000
0.00
headers to connect supernode PCBs laterally
4.1000
16.40
headers to connect supernode PCBs vertically
0.0000
0.00
old computer power supplies for +5V rail
30.6300
30.63
for SMD soldering
11.4900
22.98
for SMD stencil
600.00
supernodes, rows, columns
997.70
Schedule
Nate
Accomplishments by CDR
A review
 Super-node hardware prototype
 Demo firmware
(Kind of)
 24 channel PWM
 Runs simple autonomous patterns/scripts on supernode
 All parts selected (sensors, LED drivers)
 Know how to program Nios II soft-core
Nate
What’s left?
 Physical assembly
 Kapton stencil + solder paste + pick and place = PCA
 Insert through-hole LEDs by hand
 Attach through-hole headers by hand
 Acrylic base for structure and æsthetic
 Coding
 Xmega and Nios II
 Basics are down, now we just need the specifics
Nate
Potential Problems/Concerns
 Noise on the board
 Fast switching LEDs – 20 mA @ 1 kHz
 Lots of serial communications everywhere
 Inductive kickback
 Relatively large current loops to LEDs
 Communication with LED driver
 SPI?
 Bit-banging?
 I2C capacitance
 Using I2C buffer/driver (LTC4300A)
 Time!
Nate
Milestone 1
 PDR goals
 “Puppet” mode (FPGA direct control)
 More super-nodes (a full module = 8 super-nodes)
 Establish intercommunication
 Power supply (160 W @ 5V)
 New goals
 Build a supernode
Amit
Milestone 2
 Full cube construction
 More complex super-node autonomous scripts
 Environmental input
 Simple algorithmic games (GOL)
 Be ready for expo
Amit
Questions?