Questions tagged [progmem]
PROGMEM is a keyword used when declaring a variable that keeps the data in flash instead of copying it into SRAM. It is part of the `pgmspace.h` library. Use this tag for discussions about using this attribute.
66 questions
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How to manage mixed pointers to RAM and PROGMEM on Arduino?
I'm working on a project where I want to implement something like a FORTH interpreter on Arduino. The interpreter consists of "WORDS," where each WORD has a name, a header, and an array of ...
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How do I fix display showing random pixels on ST7789V2 LCD Module?
Problem Description:
I’m trying to interface a Waveshare 1.69-inch LCD module (ST7789V2 driver, 240x280 resolution) with an Arduino UNO board. I’ve connected all the necessary ports as per the ...
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Large arrays crash the arduino
I have three large PROGMEM arrays, in order to store musical notes for a song. One array is the notes, one is the note durations, and one is the pause after the note.
The first array is an int one and ...
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Can I use [[__progmem__]] instead of PROGMEM?
In pgmspace.h, PROGMEM is defined as __ATTR_PROGMEM__, which is defined as __attribute__((__progmem__)). AFAIK, __attribute__ is GNU only. Since C++ 11, we have the attribute specifier sequence.
I can'...
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PlatformIO and const PROGMEM
I'm using the DuinoWitchery LCD library (https://github.com/duinoWitchery/hd44780) in a PlatformIO Arduino project with CLion.
The following code works if I stick it in main.cpp:
// near top of class.....
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Send a 2d PROGMEM array over SoftwareSerial
I have a 2d array:
const byte messages_for_measurement[2][8] PROGMEM =
{
{ 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08 },
{ 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10 },
};
I want to send ...
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Is there a good reference for Arduino Due memory architecture and usage?
It's been harder than I expected to find a reference source or usage guide.
There's a number of sources I've looked at along the road to this question:
The Due is listed here and here as having 512KB ...
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strcpy_P increases IROM usage by 400%
Using ESP8266 (NodeMcu 1) in Arduino IDE:
I can't upload my sketch because a single call to strcpy_P seems to increase the IROM usage by about 400%: 25% total usage without the call, 100+% with the ...
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Read bytes from PROGMEM array
Disclaimer: I just started using C++ and I'm a bit of a beginner. Keep that in mind as your answering.
So I recently bought my first Arduino. It's a customized one and it has an 8x8 display attached ...
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PROGMEM for IR command storage
I'm working on a code that is able to send raw data as IR signal to IR transmitter,
the memory of arduino Nano is not enough to store the array in SRAM storage,so i'm about to use PROGMEM to store ...
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How can a function/method determine if a const array passed in is PROGMEM (flash) or not (RAM)?
Is it possible for a function/method to know if a constant array that has been passed in is in flash or RAM?
If I have a method or function that receives a constant array that is in RAM, the array is ...
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Reading PROGMEM results in an incorrect hex value [closed]
I'm sure I'm doing something stupid here, but the code below is supposed to write the test hex values to a I2C EEPROM, however when I attempt to read the EEPROM it has the wrong values. Directly ...
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How to create large progmem arrays and not annoy the linker
I have a rather complex project (PlatformIO, but I've also had this happen in the vanilla IDE) with several nested includes.
Let's say that there are three files and a main sketch.
The main sketch ...
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Initialize object with PROGMEM constants
I have a class which has a const char * property:
class A
{
public:
const PROGMEM char* text;
};
void setup()
{
// A a{"Hello World!"};
// A a{PSTR("...
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ESP8266 compilation error: "previous declaration of 'HTTPMethod HTTP_HEAD'"
I have an ESP8266 program that used to work but is now failing to compile with this error:
C:\...\Arduino\libraries\WiFiManager/WiFiManager.h:25:24: note: in expansion of macro 'PROGMEM'
const ...
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