M2tklib Rotary Encoder Example (problem)

Using Arduino Project Guidance
1

Dear Community,

I am working on a project which needs a menu style of interface where I can vary 2 values. I found the rotary encoder example of the M2tklib. Initially, the sketch displays 2 digit values on a range from 0 to 99. I need values at a range from 0 to 999. I found a way to plot 3 digits. However the variables which store the values when changed with the rotary encoder do not reach 999. Specifically, it can go from 0 to 255. The data type of the variables are "uint8_t". I believe that is the reason which does not let me to plot values greater than 255. Changing the data type of the variables gives me errors that I do not know how to solve. Any input is welcomed. I am providing below the code which plots 3 digits.

/
#include "U8glib.h"
#include "M2tk.h"
#include "utility/m2ghu8g.h"

U8GLIB_SSD1306_128X64 u8g(U8G_I2C_OPT_NONE);
//=================================================
// Forward declaration of the toplevel element
M2_EXTERN_ALIGN(top_menu);

//=================================================
// Simple dialog: Input two values n1 and n2

uint8_t n1 = 0;
uint8_t n2 = 0;

M2_LABEL(el_l1, NULL, "value 1:");
M2_U8NUM(el_u1, "c3", 0, 255, &n1);
M2_LABEL(el_l2, NULL, "value 2:");
M2_U8NUM(el_u2, "c3", 0, 255, &n2);

M2_LIST(list) = { &el_l1, &el_u1, &el_l2, &el_u2 };
M2_GRIDLIST(el_gridlist, "c2", list);
M2_ALIGN(top_menu, "-1|1W64H64", &el_gridlist);

// m2 object and constructor
// Note: Use the "m2_eh_4bd" handler, which fits better to the "m2_es_arduino_rotary_encoder" 
M2tk m2(&top_menu, m2_es_arduino_rotary_encoder, m2_eh_4bd, m2_gh_u8g_bf);

//=================================================
// Arduino Setup & Loop

void setup(void) {
  
// Connect u8glib with m2tklib
  m2_SetU8g(u8g.getU8g(), m2_u8g_box_icon);

// Assign u8g font to index 0
  m2.setFont(0, u8g_font_7x13r);

// define button for the select message
  m2.setPin(M2_KEY_SELECT, 7);          // dogm128 shield, 2nd from top
  
// The incremental rotary encoder is conected to these two pins
  m2.setPin(M2_KEY_ROT_ENC_A, 3);
  m2.setPin(M2_KEY_ROT_ENC_B, 2);
}

void loop() {
  // check rotary encoder also inside the picture loop
  m2.checkKey();  
  // process events and redraw menu if required
  if ( m2.handleKey() != 0 ) {
    u8g.firstPage();  
    do {
      // check rotary encoder also inside the picture loop
      m2.checkKey();
      // draw menu
      m2.draw();
    } while( u8g.nextPage() );
  }
}

What was changed to the initial code to plot 3 digits from 2 digits was the below code

M2_LABEL(el_l1, NULL, "value 1:");
M2_U8NUM(el_u1, "c2", 0, 99, &n1);
M2_LABEL(el_l2, NULL, "value 2:");
M2_U8NUM(el_u2, "c2", 0, 99, &n2);

Trying to change n1, n2 from "uint8_t" to "int" which I though that it would solve my problem gives me the following error;

error: cannot convert 'int*' to 'uint8_t* {aka unsigned char*}' in initialization
 
#define M2_U8NUM(el,fmt,min,max,variable) m2_el_u8_ptr_t el M2_SECTION_PROGMEM = { { { m2_el_u8num_fn, (fmt) }, (min), (max) }, (variable) }

exit status 1
Error compiling for board Arduino Uno.

Thank you,

C_iak

2

It appears that the library only supports having 8 bit variables that can be associated with the menu. This means you will have to come up with a different strategy.

A kludge would be to have a second variable that represents 100s and keep your original variable that represents 0-99 and then you would have to combine them whenever you wanted to use the actual value.

3

Hi blh64,

Thank you for the heads up. Do you think that modding the entire library and substituting every "uint8_t" entry with "uint16_t" is going to do the trick?

Otherwise, how would you go and do the kludge you are talking about? I am saying this because if the library is designed to spit out 8-bit integers how is it going to plot 16-bit int's for instance?

Thanks,

4

PROBLEM SOLVED

Turns out the library supports uint32_t variables.

Thus what is needed to change is;

uint8_t n1 = 0;
uint8_t n2 = 0;

M2_U8NUM(el_u1, "c3", 0, 255, &n1);
M2_U8NUM(el_u2, "c3", 0, 255, &n2);

into

uint32_t n1 = 0;
uint32_t n2 = 0;

M2_U32NUM(el_u1, "c3", &n1);
M2_U32NUM(el_u2, "c3", &n2);

Warning!

the M2_U32NUM takes 3 arguments instead of 5. Also, the end result changes each digit individually

5