LED Matrix

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kevinnths
 
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LED Matrix

Post by kevinnths »

When I upload the code, i got this problem. How can i fix it?

C:\Users\Kevin\Documents\Arduino\libraries\Ada_HT1632_master\glcdfont.c:15:23: error: variable 'font' must be const in order to be put into read-only section by means of '__attribute__((progmem))'

static unsigned char font[] PROGMEM = {

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adafruit_support_bill
 
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Re: LED Matrix

Post by adafruit_support_bill »

That is a known issue with the most recent IDE. See the second question here: https://github.com/arduino/Arduino/wiki ... -Questions
You will need to edit the library to add the 'const' as described in the FAQ

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curtis_r
 
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Re: LED Matrix

Post by curtis_r »

Just received my 16x24 LED display & am trying the basic demo. I've tried the GitHub suggestion, namely changing in glcdfont.c
static unsigned char font[] PROGMEM = {
to
const font[] PROGMEM = {

but it then produces a new error:
warning: type defaults to 'int' in declaration of 'font'

Arduino Uno, software v1.6.6

edit: had also tried const char font[] PROGMEM = {

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adafruit_support_mike
 
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Re: LED Matrix

Post by adafruit_support_mike »

Code: Select all

static const unsigned char font[] PROGMEM = {
compiles without complaint for me under 1.6.6

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curtis_r
 
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Re: LED Matrix

Post by curtis_r »

That did it! Obviously I'm new to C++ coding (and really haven't coded anything in ages). Thanks a ton.

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curtis_r
 
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Re: LED Matrix

Post by curtis_r »

Ok, now that I have the examples working, I think I might have a defective LED panel. I've tried a few 'examples' with the same dead LEDs.
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adafruit_support_bill
 
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Re: LED Matrix

Post by adafruit_support_bill »

Yes, that looks like you have a couple of dead sections there. It is an SPI interface, so it is not a wiring problem on your end. If you contact [email protected] with a link to this thread we can send a replacement.

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Joeyherbst
 
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Re: LED Matrix

Post by Joeyherbst »

How do I find the line of code in the library to change it?

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adafruit_support_bill
 
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Re: LED Matrix

Post by adafruit_support_bill »

How do I find the line of code in the library to change it?
What are you trying to change?

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Joeyherbst
 
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Re: LED Matrix

Post by Joeyherbst »

char font[] PROGMEM = {
To whatever it needs to be

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adafruit_support_bill
 
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Re: LED Matrix

Post by adafruit_support_bill »


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Joeyherbst
 
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Re: LED Matrix

Post by Joeyherbst »

Alright so I found it and I changed it and now it is not letting me save the changed wordpad doc. How do I save it once it's changed? It is giving me the error: 'This file is a read only file.

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adafruit_support_bill
 
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Re: LED Matrix

Post by adafruit_support_bill »

right-click on the file in explorer and un-check the read-only box.

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Joeyherbst
 
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Re: LED Matrix

Post by Joeyherbst »

Alright so I changed and saved the file and now i can verify it fine but when I upload it it uploads fine but nothing happens.

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adafruit_support_bill
 
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Re: LED Matrix

Post by adafruit_support_bill »

Please post some photos showing your soldering and connections between the Arduino and display.

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