Hi
What is the maximum lenght of a mini pov message.
Thanks
Max lenght of minipov message
Moderators: adafruit_support_bill, adafruit
Please be positive and constructive with your questions and comments.
-
- Posts: 1645
- Joined: Sat Nov 10, 2007 12:59 am
Re: Max lenght of minipov message
the default firmware stores the message in sram, which at 128 bytes is a scarce resource on the attiny2313.
the largeimage.c version of the firmware moves the message data to program memory which is 2048 bytes. so you've got 2048 columns minus the size of the program itself and the program's pretty small.
if you use firmware that has a font built in, depending on how many characters you have defined, you can display text strings of up to around 1000 characters. i wrote a version for use with uv leds that has all 96 printable ascii characters defined that has room for about 950 characters of text. it can be had here, but you'll want to change the initialization code for the timer in order to use it as a regular pov device.
to get a 400hz interrupt frequency use something like thisthere is also code to introduce delays between lines of text, that you might want to adjust. these are controlled by the variables pauseBefore and pauseAfter. you'll need to change their declarations from uint8_t to uint16_t. after changing the interrupt code, as above, a value of 400 in either variable will introduce a delay of 1 second.
why? i don't know. i thought maybe i'd swing a minipov at the end of a very long piece of string, but i never did.
the largeimage.c version of the firmware moves the message data to program memory which is 2048 bytes. so you've got 2048 columns minus the size of the program itself and the program's pretty small.
if you use firmware that has a font built in, depending on how many characters you have defined, you can display text strings of up to around 1000 characters. i wrote a version for use with uv leds that has all 96 printable ascii characters defined that has room for about 950 characters of text. it can be had here, but you'll want to change the initialization code for the timer in order to use it as a regular pov device.
to get a 400hz interrupt frequency use something like this
Code: Select all
//
// setup timer 0, 1/256 prescale, mode 7, 400Hz, enable interrupt
//
TCCR0A = (1 << WGM01) | (1 << WGM00); // select fast pwm w/ top = OCR0A
TCCR0B = (1 << WGM02) | (1 << CS02); // and prescale = 256
OCR0A = 78; // gives interrupt freq ca 400Hz
TIMSK = (1 << TOIE0); // enable overflow interrupt
sei (); // enable interrupts
why? i don't know. i thought maybe i'd swing a minipov at the end of a very long piece of string, but i never did.
-
- Posts: 9
- Joined: Sun Mar 01, 2009 4:37 pm
Re: Max lenght of minipov message
Thanks for precise answer.
I will study it.
You speak about a system with uv led. I am about to work with them.
Is there some very important things to know about them or can i use them like "classic" led.
Ciao.
I will study it.
You speak about a system with uv led. I am about to work with them.
Is there some very important things to know about them or can i use them like "classic" led.
Ciao.
-
- Posts: 9
- Joined: Sun Mar 01, 2009 4:37 pm
Re: Max lenght of minipov message
but i don't really understand what you mean :
.
I am not from US/GB.
Code: Select all
why? i don't know. i thought maybe i'd swing a minipov at the end of a very long piece of string, but i never did.
I am not from US/GB.
-
- Posts: 1645
- Joined: Sat Nov 10, 2007 12:59 am
Re: Max lenght of minipov message
sorry for not being clear. 900+ characters is a lot of arm swinging with a minipov. what i meant to suggest was that one could tie a few feet of strong string to each corner the minipov and swing it in circles over one's head.zettaman wrote:but i don't really understand what you mean
like i said, i didn't try it. mostly due to not having 900 characters worth of wisdom to share with the world and also due to worries about the amount of momentum an accidentally released minipov might have.
-
- Posts: 9
- Joined: Sun Mar 01, 2009 4:37 pm
Re: Max lenght of minipov message
OK i understood.
I won't use large text with my arms...
I'll send you photo if you want!....
I won't use large text with my arms...
I'll send you photo if you want!....
Please be positive and constructive with your questions and comments.