Help adding E-Ink display support

I've got some code that may be helpful. I'm able to do a partial refresh on my Watchy using this, although the LUT is not quite right (seems very dark compared to regular full refresh). First of all, I extended some of your commands.. I didn't see you calling cmd(0x12) (software reset) so I created a fullReset():

SSD16xx.prototype.fullReset = function() {
  return new Promise((resolve)=>{
    digitalWrite(this.resetPin, 0);
    setTimeout(()=>{
      digitalWrite(this.resetPin, 1);
      this.sc(0x12);
      this.partial=false;
      setTimeout(resolve,this.hwResetTimeOut);
    },this.hwResetTimeOut);
  });
};

I also use this to send commands WITH data, then wait (if necessary) for the RST pin (some commands are so fast that a watch on RST falling doesn't register):

SSD16xx.prototype.waitCmdData = function(command, data){
  return new Promise((resolve,reject)=>{
    console.log("sending a busy command!");
    this.sc(command);
    this.psd();
    this.sd(data);
    if(this.busyPin.read()) 
      setWatch(resolve, this.busyPin, { repeat:false, edge:'falling' });
    else
      resolve();
  });
};

This sets up using partial refresh by uploading a special LUT:

SSD16xx.prototype.setFastRefresh = function() {
  const WF_PARTIAL = new Uint8Array([ 0x0,0x40,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x80,0x80,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x40,0x40,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0, 0x0,0x80,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0, 0xF,0x0,0x0,0x0,0x0,0x0,0x1,0x1,0x1,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0, 0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0, 0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x22,0x22,0x22,0x22,0x22,0x22,0x0,0x0,0x0,0x02,0x17,0x41,0xB0,0x32,0x28,
    ]);	

  this.fullReset().then(()=>{
    this.waitCmdData(0x32, WF_PARTIAL.slice(0,153)).then(()=>{
      this.scd(0x3F, WF_PARTIAL[153]);
      this.scd(0x03, WF_PARTIAL[154]);
      this.scd(0x04, WF_PARTIAL.slice(155, 158)); 
      this.scd(0x2C, WF_PARTIAL[158]);
      this.scd(0x37, [0,0,0,0,0,0x40,0,0,0,0]); 
      this.waitCmdData(0x3C, 0x80).then(()=>{
        this.partial = true;
      });
    });
  });
  
};

It sets an internal flag (partial) so the flip() command knows what to send:

SSD16xx.prototype.flip = function() {
    this.scd(0x4E, 0);
    this.scd(0x4F, [0,0]);
    this.scd(0x24, this.g.bw.buffer);
  
    if(this.display.coloredDisplay){
        this.scd(0x4E, 0);
        this.scd(0x4F, [0,0]);
        this.scd(0x26, this.g.cw.buffer);
    }
  
    if(this.partial) {
      print("flip:partial");
      this.scd(0x22, 0xcf);
    } else {
      print("flip:full");
      //this.scd(0x22, 0xF7);
    }
    return this.refreshDisplay();
};

That much works for me on the Watchy. Hope it helps. Like I said, LUTs are tricky things, so your results may be better/worse. I'm still trying to figure the out...