Timeout on I2C Write BUSY - not all the time [Adafruit 8x8 matrix backpack]

...and with a variable you can control the logging - even when connected - and enhanced with a watch dog for setup - sDog - which - if setup not successful - restarts. Timing may be adjusted because it is dependent on all the retries w/ the timeouts cumulated plus some reserve and pause that can and should happen under its watch. You may setup another watch dog for running / sending the texts / grpahics ( envoieMatrice() ).

PS: é, I like the francophonisation of - not just - les noms... <;:{ooops}>>>

var lon = false // logging is on / off
,   log = function() { console.log.apply(console,arguments); } 

, sDog = null // setup watch dog

, ini = function() { // first
  require("Font4x6").add(Graphics);
  // initialisation I2C
  if (lon) log("setup I2C");
  I2C1.setup({scl: B6,sda: B7});
  /* rajouter les init de connexion pour le display */
  if (lon) log("init programme affichage matrice v2.2 - éric choisy ©2019");
  if (lon) log("mém. utilisée: "+Math.round(process.memory().usage/proc­ess.memory().total*100)+"%");
 }
, osc = function(tries) { if (tries>0) { // w/ retries
  try { if (lon) log("turn OSC ON");
    digitalPulse(LED2,1,20); // verte
    I2C1.writeTo(0x70, 0x21); // turn on oscillator
    setTimeout(don,250,2);
  } catch(e) { if (lon) log(e);
    setTimeout(osc,250,--tries);
    digitalPulse(LED1,1,20); // rouge
  } } else if (lon) log("Unable to turn osc on"); }
  
, don = function(tries) { if (tries>0) { // w/ retries
  try { if (lon) log("turn display ON");
    digitalPulse(LED2,1,20); // verte
    I2C1.writeTo(0x70, 0x81); // display on
    setTimeout(lum,250,2);
  } catch(e) { if (lon) log(e);
    setTimeout(don,250,--tries);
    digitalPulse(LED1,1,20); // rouge
  } } else if (lon) log("Unable to turn display ON"); }

, lum = function(tries) { if (tries>0) { // w/ retries
  try { if (lon) log("set brightness");
    digitalPulse(LED2,1,20); // verte
    I2C1.writeTo(0x70, 0xE0 | 0); // luminosité 0-15
    if (sDog) sDog = clearTimeout(sDog); // clear sDog
    setTimeout(envoieMatrice, 1000);
  } catch(e) { if (lon) log(e);
    digitalPulse(LED1,1,20); // rouge
    setTimeout(lum,250,--tries);
  } } else if (lon) log("Unable to set brightness"); }

, sup = function() { // setup under setup watch dog
    sDog = setTimeout(sup,5000); // retry every 5 secs
    osc(3); } // starts the chain \:
;
const onInit = function() {
  ini();
  sup(); // setup under sDog - setup watch dog monitor
};