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Questions tagged [char]

9 questions
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1 answer

How do I convert a structure to a char[] for use in Wire.h, or is there a better way?

I need to interface an ATTiny88 MCU configured as an I²C slave with a Raspberry Pi configured as an I²C master. I may be using the wrong approach, but I have a structure consisting of four different fixed length data types I want to pass back to…
LesRhorer
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Assign a list of char *

Explain in a simple example. How to pass a char* to a function? #define name1 "ABCD" #define name2 "EFGH" #define name3 "HIJK" char *list[3] = {}; void printList(char *l, int x) { for (int i = 0; i < x; i++) { Serial.println(l[i]); …
guyd
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How can I make this function take up less memory?

I've written a sketch that uses TimeLib to display elapsed time. I'm measuring how long it takes to drain a battery. The goal is to display the time as hh:mm:ss. The code I use works well when I create a sketch that only contains this code. But when…
Hobbes
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Problem saving "char" variable to EEPROM on ESP32

I am making a project, in which I need to store the WiFi credentials to the EEPROM. For now, I am able to store a bool array in the EEPROM, but I am not able to store the char variables as the ESP32 crashes. I can't share the complete code since it…
Loic Daigle
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Construct Strings with UTF-8 characters from data

I am printing some ASCII art to the Serial monitor from Arduino UNO, with some success. However, using string literals uses more memory than I would like. I wanted to try constructing the strings/chars from other data types so that I can manipulate…
Hubert B
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Problem cleaning string read from serial buffer

I am trying to move a stepper motor when a specific command is send to Arduino Mega 2560. This command is read character by character and stored in a string variable. Whenever a new command is sent, an act should be performed. However, it is not…
Yan Araújo
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char * variable - Handle correctly to avoid overflow

I'm trying to understand if a char * variable can be updated down the code (since it only stores a pointer) or over-flow can occur. For example: char *A="/file.txt"; char *B; void print_filename(char…
guyd
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pointing to array of chars

I'm trying to pass a list of files (located in sketch) to be read using a library I write. List can have different filenames and vary in number of files. How to pass a this array to my library? for example: char *parameterFiles[3] =…
guyd
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Char array filling with blanks

When I run this code, my pin and pinCheck arrays are not being filled with the results of keypad.getKey(). If I print the value at each index, the result is blank. As far as I can tell, I am either not writing a char to the array, I am misreading…
Ryan
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