LED Light ShowLED Light ShowCritical Design ReviewCritical Design Review

Team LitMichael Hatt

Scott Butler

Kristin Haeusler

Brock Smith

System OverviewSystem Overview We are using a Spartan 3 controller board to output a light

pattern to 4 LED boards. Each board contains 16 sets of red, green, and blue LEDs Each LED will have 8 bit varying levels of brightness (256

shades). Theoretically each set of 3 LEDs will be able to display 256^3-almost 17 million colors! (if the color blends, BIG if)

• 2 modes:1. Manual-outputs one of several stored patterns chosen by

the user.2. Serial-mode-FPGA takes input from the computer and

outputs a corresponding pattern to the LED boards.

System LimitsSystem Limits

The Limit of the system is the shift registers on the LED boards

These boards run reliably at a speed of 5 MHz

The latch rate will then depend on the amount of boards daisy chained together.

For 4 boards the latch rate is 26 kHz

We will go on to the section of the pattern for each LED at 101 Hz, this the is the “refresh rate”

All of these frequencies are much faster than the eye can register change

Manual ModeManual Mode

User will choose between three pre-determined patterns.

Only the initial states of the LEDs will be stored on the FPGA. The rest of the pattern will be determined by feeding the output through various logic gates and looping the new pattern back into the RAM.

This way the pattern will change every cycle.

Serial-ModeSerial-Mode

FPGA will take RS-232 input, convert into usable data, and output corresponding pattern to LEDs.

The user programs a pattern from a PC, we will use the hyper terminal but it could be expanded, which is then sent through a RS-232 port to the FPGA.

System Block DiagramSystem Block Diagram

Schematic of LED boardsSchematic of LED boards

SER

14

SRCL

K11

SRCL

R10

RCLK

12

G13

QA15

QB1

QC2

QD3

QE4

QF5

QG6

QH7

QH9

SER

14

SRCL

K11

SRCL

R10

RCLK

12

G13

QA15

QB1

QC2

QD3

QE4

QF5

QG6

QH7

QH9

SER

14

SRCL

K11

SRCL

R10

RCLK

12

G13

QA15

QB1

QC2

QD3

QE4

QF5

QG6

QH7

QH9

SER

14

SRCL

K11

SRCL

R10

RCLK

12

G13

QA15

QB1

QC2

QD3

QE4

QF5

QG6

QH7

QH9

SER

14

SRCL

K11

SRCL

R10

RCLK

12

G13

QA15

QB1

QC2

QD3

QE4

QF5

QG6

QH7

QH9

SER

14

SRCL

K11

SRCL

R10

RCLK

12

G13

QA15

QB1

QC2

QD3

QE4

QF5

QG6

QH7

QH9

SER

14

SRCL

K11

SRCL

R10

RCLK

12

G13

QA15

QB1

QC2

QD3

QE4

QF5

QG6

QH7

QH9

74HC59574HC59574HC595 74HC59574HC59574HC59574HC595

N/C

N/C

N/C

Data

N/C

N/C

N/C

N/C

Latch Latch

DataClock

N/C

Clock

N/C

N/C

N/C

N/C

N/C

N/C

FPGA Internal SchematicFPGA Internal Schematic

ModularityModularity

Parts repeated for each set of boards:– Reader,Manual Writer, Switchers, RAM, LED

controller, Pattern changer

Single-use parts: – State Machine, Stored patterns, RS-232

Controller, Computer Writer, LCD Controller

State MachineState Machine

Takes an input from user keypad– User will press button to change state (mode)

Outputs the current state to nearly every block of the controller

6 states: 3 pre-programmed patterns, serial mode, initialization, and reset

LCD controllerLCD controller

Inputs: Current StateOutputs: Sends data to LCDOutputs data in ASCII format to display the

current mode on the LCD, according to the State Machine.

Dual-Port RAMDual-Port RAM Inputs: RAM control signals Outputs: Data being read to LED board controller We are using two 1x1536 bit chunks of RAM (4 boards*48

LEDs/board *8 bits/LED =1536) to store patterns which are output to LEDs.

Each byte of data determines the intensity/shade of each LED One half of the RAM will read in data while the other simultaneously

reads out data, as determined by the switchers. Using dual-port RAM allows us to create manual-mode patterns, via

the feedback loop, without having to use massive amounts of RAM to store a sustained pattern.

LED controllerLED controller Inputs: Pattern data from RAM Outputs: Clock, Serial data and latch signal Takes the data from RAM. Determines if LED should get a high or low and then shifts

out the correct bit. After shifting 192 bits it triggers a latch to display the

pattern After 256 cycles it moves to the set of data The LED value determines the fraction of the 256 cycles

that the LED will be turned on, so as to give the appropriate shade

Data ReaderData Reader

Inputs: Clock, ResetOutputs: Address and count informationTells RAM the address of the data that is to

be sent to the LED board controllerWhen the data is ready, a “ready” signal

will also be sent to the controllerCycles through 192 addresses, then returns

to first address

Example VHDLExample VHDL

Schematics from VHDLSchematics from VHDL

Manual-mode WriterManual-mode Writer

Inputs: Pre-programmed initial-state pattern, current state, logical pattern changer.

Outputs: Address info, write enable, data from input

When activated by state machine, the writer takes pre-programmed pattern, then after one cycle, takes the altered pattern from the logic changer, and writes it into the RAM.

Main purpose is to write new data to RAM, while other half of RAM is being displayed

Serial-Mode WriterSerial-Mode Writer

Inputs: RS-232 data, state machineOutputs: Address, data, write enableTakes converted RS-232 input and writes it

into the RAM when activated by the state machine

RAM Input SwitcherRAM Input Switcher

Inputs: Data reader outputs, manual and serial-mode writer outputs

Outputs to RAMRoutes all data and signals to the

appropriate half of the RAMContinuously switches between the two

halves of the RAM at the correct time

RAM output switcherRAM output switcher

Inputs: Outputs of RAM Outputs: Data and control signals being read to

LED controller Takes output data from RAM and outputs data

from one of the two halves of RAM, in an alternating manner.

Synchronous with the input switcher to assure that one chunk of RAM is reading in data while the other chunk is outputting data.

Stored DataStored Data

No inputsOutputs: Data to be written to RAMStores initial data patterns for first cycle of

manual modeOnly stores 4*48 bytes of dataThe entire duration of the pattern is

determined by this initial data

Pattern ChangerPattern Changer

Inputs: Current State, Data being read to LED controller

Outputs: Changed dataTakes each byte being read out and changes

it using pre-determined logic circuitryPrepares altered data for next cycle as

previous data is being read out

RS-232 controllerRS-232 controller

Inputs: Data from RS-232 portOutputs: Data(in bytes)Communicates with the RS-232 port to

gather data from the computer.Converts the input data to a form that is

ready to be written into RAM.

Parts ListParts List

Spartan-3 Development Kit $100 PCBs(provided) ~$650.00 LEDs(3840) ~$800 Optrex DCM 16433 LCD (acquired) $7.00 2 Power Supplies(5V @ 40 A) ~$400 Resistors,etc. ~$80 Shift registers ~$80

Grand Total: $2117

Electricity bill to power this wall: too much

ScheduleSchedule

GoalsGoals

Milestone 1:– Manual Mode working

Outputs changing patterns to board

Intensity varies

– LCD working Milestone 2:

– Reading data from RS-232 port

– Mode switching works

EXPO:– Serial Mode working– Can easily switch

between modes– Change patterns with

keypad– Documentation

complete

Division of LaborDivision of Labor

Scott– RS-232 controller– RAM controllers

Michael– RAM controllers– LED controller

Kristin– Pattern changer– Stored pattern– RAM controllers

Brock– LCD controller– state machine– switchers

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