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16  Community / Exhibition / Gallery / Re: Scrolling LED matrix display - Parola for Arduino on: April 02, 2014, 02:54:54 am
MD_MAX72XX repo has been updated with new begin() code to initialise OP_DECODEMODE. Let me know how you all go.
17  Using Arduino / Programming Questions / Re: How to run code while a delay is in place on: April 02, 2014, 02:46:39 am
You can't.

Look at the blink without delay example to see how you can do it using the millis() timer.
18  Community / Exhibition / Gallery / Re: Scrolling LED matrix display - Parola for Arduino on: April 01, 2014, 03:57:18 pm
OK. Will try this on the week end. DECODEMODE was not implemented as it does not relate to the LED matrices, but easy enough to add it into the control switch and it can't hurt.

The datasheet is fairly clear on what happens on reset:
Quote
On initial power-up, all control registers are reset, the display is blanked, and the MAX7219/MAX7221 enter shutdown mode. Program the display driver prior to display use. Otherwise, it will initially be set to scan one digit, it will not decode data in the data registers, and the intensity register will be set to its minimum value.
but I guess these clone chips don't conform.
19  Community / Exhibition / Gallery / Re: Scrolling LED matrix display - Parola for Arduino on: April 01, 2014, 02:08:33 pm
Bill, which library clears the modules? I can compare the initialisation code this week end. I see what you describe occasionally but a power cycle is enough with my modules, and usually more than 8 modules rather than 6.
20  Using Arduino / Programming Questions / Re: Weird little math problem on: April 01, 2014, 06:25:36 am
Quote
8000*potvalue/1000    would optimise to  8*potvalue ,   not to 8*potvalue/1000

Yup. You spotted my deliberate mistake smiley
21  Community / Exhibition / Gallery / Re: Scrolling LED matrix display - Parola for Arduino on: April 01, 2014, 06:23:18 am
A solution has been proposed earlier in this thread involving powering down the display and then resetting the  7219s. Look for it.
22  Using Arduino / Programming Questions / Re: Weird little math problem on: March 30, 2014, 09:47:37 pm
Code:
target_rpm = (8000*potvalue)/1000 + 1000

My guess is that this works because the compiler optimises the expression to

Code:
target_rpm = (8 * (potvalue/1000) ) + 1000

However, looking at this potvalue/1000 will always be 0 (assuming raw pot value fro Arduino 0..1023) except for the few cases between 1000..1023, so the expression will only evaluate to 1000 or 1008. Do you get a range of values or just 2?
23  Using Arduino / Programming Questions / Re: Weird little math problem on: March 30, 2014, 08:04:04 pm
Almost surely an integer math problem, but you need to supply the declaration of variables to be sure.

an unsigned int holds up to 65535, so if potvalue is 8 or more you will overflow. try making target_rpm and all the other variables unsigned long and see if the problem persists.
24  Using Arduino / Displays / Re: Menu Example Sketch on: March 30, 2014, 04:17:06 pm
MENWIZ is reasonably easy to use, and you can use it with any setup. You will have to write to code to handle the buttons on the LCD if they are not on/off switches (or you can use my analog buttons library in the code repository, link below).
25  Using Arduino / Project Guidance / Re: Row 16 x Col 16 led matrix, help on: March 30, 2014, 05:38:09 am
You need to provide information on the hardware, post your software and then ask a question you need with. We cannot read your mind.
26  Using Arduino / LEDs and Multiplexing / Re: Two independent things at once on: March 30, 2014, 05:34:35 am
You need to remove all the delay() calls in the code. Loki at the blink without delay example and see how millis() is used to keep track of when to do things. You will also probably need to read up a bit on finite state machines before too long as well.
27  Using Arduino / LEDs and Multiplexing / Re: Using Gammon's LED Flasher library with a state machine? on: March 29, 2014, 07:11:50 pm
Set the digital output to the state that you need as you enter the next state, as you have done.

Or just add a method to the library to do the same thing (like reset() or something). This could allow you to reset timers as well..

UPDATE: I just check the library header file and the object has everything you need...

Code:
    void begin ();
    void update ();
    void on ();
    void off ();
    bool isOn () const;
28  Community / Exhibition / Gallery / Re: Scrolling LED matrix display - Parola for Arduino on: March 29, 2014, 02:16:37 pm
@Alhooti - It supports different fonts but not the scripting requirements. As per previous post, this is too specific for this type of library.

@bill - I used the same sort of technique for my resistors, and yes the tab on the matrix makes sense. I guess they only go in 2 ways so if the first doesn't work ...
29  Using Arduino / LEDs and Multiplexing / Re: Using Gammon's LED Flasher library with a state machine? on: March 29, 2014, 04:43:38 am
If you don't call update() the led won't flash...
30  Community / Exhibition / Gallery / Re: Scrolling LED matrix display - Parola for Arduino on: March 29, 2014, 12:20:45 am
Bill - not sure I get what is happening to the file. The download (zip) has the doc file - can you please download that and see if yours are different from the published one (also generated using doxygen).

I saw an effect where everything was on one line when I didn't know what doxygen was doing - to have it as 'code' it needs 4 spaces at the start of the line. If that is missing doxygen will do its normal 'folding' of lines as it pleases.
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