Go Down

Topic: [solved] Mega2560 for a 8x8x8 RGB Cube (Read 6918 times) previous topic - next topic

alsoft

Jun 03, 2013, 07:04 pm Last Edit: Jun 11, 2013, 03:37 pm by alsoft Reason: 1
Hello i'm a beginner with Arduino so if someone can help me great

I have build a 8x8x8 RGB led cube powered with a Arduino UNO or standalone atmega328P and everything works fine. The sketch for the cube is made by someone else and i did make some effects myself but the memory on the atmega328P got to small so i bought a Mega2560 because of the memory. The 25 shift registers (74HC595) are connected with 4 wires of the UNO pin 2 (latch), pin 4 (blanc), pin 11 (MOSI), and pin 13 (SCK).
I notice that on the MEGA2560 the MOSI pin is 51 and the SCK pin is 52 so i changed that in the sketch and the wires but the cube won't work, it compiles/writes without errors, i can see that the program runs with Serial.print but some of the leds in the cube go on and stay on and it does nothing what it should do. So if someone have a suggestion

Attached is the code which work on the UNO ( with pin 2, 4, 11, 13)

A video of my 8x8x8 RGB LED Cube Build (long version)
 http://www.youtube.com/watch?v=GGhpgE0YRg8

CrossRoads

What pin is SS on the Mega? 50,  or 53?

I don't understand why the hardware SS pin, D10, is not used here - it must be set to an output anyway, so why not use it as the latch_pin??

#define latch_pin 2// can use any pin you want to latch the shift registers

Change 2 to 10 for an Uno, and to 50 or 53 for a Mega


These lines should not be needed at all, the SPI library takes care of assigning them:

#define data_pin 11// used by SPI, must be pin 11
#define clock_pin 13// used by SPI, must be 13

pinMode(data_pin, OUTPUT);//MOSI DATA
pinMode(clock_pin, OUTPUT);//SPI Clock

Same here, these are the defaults:

SPI.setBitOrder(MSBFIRST);//Most Significant Bit First
SPI.setDataMode(SPI_MODE0);// Mode 0 Rising edge of data, keep clock low
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

alsoft

Thanks CrossRoads for the quick reply

I did try what you wrote;
If i change #define latch_pin 2 to #define latch_pin 10 also the wired pin offcorse than the cube wont work anymore with the UNO and it don't work with the MEGA2560 #define latch_pin 53 or 50(MISO??) also. With pin 50 all the 512 leds go on full and stay full, with pin 53 a few go on but no effect movement.

Removed the lines you said except SPI.setDataMode(SPI_MODE0);// Mode 0 Rising edge of data, keep clock low

If i delete that line some leds go full on when i write a new sketch to the arduino, so when this line is active the whole cube goes off and the sketch write to the arduino like it should

The other deleted lines have no effect whatsoever with the cube what i can see with the UNO or MEGA

Do you have some other ideas??

CrossRoads

Can't offer more without seeing a schematic of what you have wired  up.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

alsoft


Can't offer more without seeing a schematic of what you have wired  up.


I've some schematics in eagle
The 25 8bit shift registers are chained together
The 4 wires goes from the Arduino UNO > Anode PCB (one 74HC959 for the levels)  > Blue PCB (eight 74HC959's for the blue color) > Green PCB (eight 74HC959's for the Green color) > Red PCB (eight 74HC959 for the Red color of the RGB led's). The order is only importend for the DATA line ( in/out pins on the 74HC959)

The attached cathode schematic is only for one color so i have that 3 times (red/green/blue)

CrossRoads

You need 0.1uF caps on the shift registers Vcc pin going to Gnd.
This  board has 12 high current shift registers (TPIC6B595 is much better than 74HC595 for current sinking),
I have daisy chained 2 boards (2nd board just had the shift registers) to drive an 5x20 matrix of 12V LEDs, the caps make it work smoothly.
http://www.crossroadsfencing.com/BobuinoRev17/

http://www.crossroadsfencing.com/BobuinoRev17/Prototype_in_action.MOV
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

alsoft

I have caps on every shift register so that can't be the problem and even if it didn't ,the cube works good/perfect with the UNO

CrossRoads

Ok, so 51 MOSI, 52 SCK, 53 SS should do it.

Need to make blanc match the hardware too, I think this is the change needed:

// 21 = PD0
#define blank_pin 21// same, can use any pin you want for this, just make sure you pull up via a 1k to 5V

  PORTD |= 1<<blank_pin;//The first thing we do is turn all of the LEDs OFF, by writing a 1 to the blank pin

PORTD |= 1<<latch_pin;//Latch pin HIGH
PORTD &= ~(1<<latch_pin);//Latch pin LOW
PORTD &= ~(1<<blank_pin);//Blank pin LOW to turn on the LEDs with the new data

Might even go with 49 instead, PORTL bit 0, keep it all the same area of the same connector.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

alsoft

The latch from 2 to 10 ( SS )on the UNO or 53 on the MEGA didn't work

The rest i will try when i at home this evening, i'm at work now

Thanks so far

Quote
Need to make blanc match the hardware too, I think this is the change needed:

// 21 = PD0
#define blank_pin 21// same, can use any pin you want for this, just make sure you pull up via a 1k to 5V

  PORTD |= 1<<blank_pin;//The first thing we do is turn all of the LEDs OFF, by writing a 1 to the blank pin

PORTD |= 1<<latch_pin;//Latch pin HIGH
PORTD &= ~(1<<latch_pin);//Latch pin LOW
PORTD &= ~(1<<blank_pin);//Blank pin LOW to turn on the LEDs with the new data

Might even go with 49 instead, PORTL bit 0, keep it all the same area of the same connector.

CrossRoads

Ok, will check back Tuesday, I'm off to bed.
Pretty sure that's what the problem will be tho, hard coded pins not matching up between processors.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

alsoft

CrossRoad this also did't work
same results, few leds burning constant full power, no movement

Quote
Need to make blanc match the hardware too, I think this is the change needed:

// 21 = PD0
#define blank_pin 21// same, can use any pin you want for this, just make sure you pull up via a 1k to 5V

  PORTD |= 1<<blank_pin;//The first thing we do is turn all of the LEDs OFF, by writing a 1 to the blank pin

PORTD |= 1<<latch_pin;//Latch pin HIGH
PORTD &= ~(1<<latch_pin);//Latch pin LOW
PORTD &= ~(1<<blank_pin);//Blank pin LOW to turn on the LEDs with the new data

Might even go with 49 instead, PORTL bit 0, keep it all the same area of the same connector.

[/quote]

CrossRoads

Post the whole code again - I think the hard codiing for blanc and latch_pin need to be synced up, I had only discussed blanc, not realizing latch_pin might be in the same situation.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

alsoft

#12
Jun 04, 2013, 11:23 pm Last Edit: Jun 07, 2013, 10:35 am by alsoft Reason: 1
Oké
Here is the unchanged original code, and works perfect on the UNO but not on the MEGA


alsoft

I hooked up an oscilloscoop on the 4 lines and compared the lines from the UNO vs MEGA2560
Put on the two Arduino's the same sketch

The data pin 11 on the UNO and the pin 51 on the MEGA have the same signal
The clock pin 13 on the UNO and the pin 52 on the MEGA have the same signal

and here comes the problem i think with the MEGA

on the latch pin 2 on the UNO i have a signal but not on pin 2 on the MEGA
also blank pin 4 on the UNO i have a signal but not on pin 4 on the MEGA

So there is no latch and blank signal from the MEGA

I hope you can help me with this CrossRoads
or someone else

CrossRoads

Okay, so pick 2 pins you can find & change these lines from:

  PORTD |= 1<<blank_pin;//The first thing we do is turn all of the LEDs OFF, by writing a 1 to the blank pin

PORTD |= 1<<latch_pin;//Latch pin HIGH
PORTD &= ~(1<<latch_pin);//Latch pin LOW
PORTD &= ~(1<<blank_pin);//Blank pin LOW to turn on the LEDs with the new data

to these

digitalWrite (blank_pin, LOW); //The first thing we do is turn all of the LEDs OFF, by writing a 1 to the blank pin

digitalWrite (latch_pin, HIGH); //Latch pin HIGH
digitalWrite (latch_pin, LOW); //Latch pin LOW
digitalWrite (blank_pin, HIGH); //Blank pin LOW to turn on the LEDs with the new data

Will be a touch slower, can improve that once you get it working again.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Go Up