1st sound round for XPT2046 module.

devices/XPT2046.js

@@ -0,0 +1,106 @@
+/* Copyright (c) 2013 Gordon Williams, Pur3 Ltd. and 2016 muet.com See the file LICENSE for copying permission. */
+/*
+
+----- XPT2046 ------------------------- 77 vars, 85 with calibrated calculation.
+
+Module for connecting to the XPT2046 resistive touchscreen controller (pin and funcgtion compatible to ADS7843).
+
+The callback function has four arguments (X, Y, readData and module). When you move your finger on the touchscreen the X and Y coordinates are reported back, and when you lift your finger, the callback function is called once with X and Y and readData set to undefined.
+
+Connect expects a calculation function that converts raw x and raw y to x and y. Calculation formula is rawValue / rawValuePerPixel + offset for x and y. Calculation arguments are rawX, rawY, readData and module. Calculation returns x, y, readData and module.
+
+
+Usage
+
+Landscape format:
+
+```
+SPI2.setup({sck:B13, miso:B14, mosi:B15, baud: 2000000});
+var touch = require("XPT2046").connect(
+  SPI2, B10, B1, function(x, y){
+      if (x !== undefined) {
+        console.log( x + " @ " + y);
+      }
+    }, function(yR, xR, d, m) { // portrait 240 x 320
+        return [ //rawVal / valPerPx * offset
+            Math.round(xR / -121.44  + 259.707) 
+          , Math.round(yR /   88.904 + -19.781)
+          , d, m
+          ];
+    }).listen();
+```
+
+Creates this output when swiping diagonally from top/left to
+bottom/right on a 240 x 320 portrait display w/ touch screen:
+
+```
+24 @ 30
+45 @ 64
+66 @ 108
+100 @ 153
+139 @ 203
+171 @ 262
+208 @ 308
+```
+
+Landscape format:
+
+```
+      ...  
+      }, function(xR, yR, d, m) { // landscape 320 x 240
+          return [ //rawVal / valPerPx + offset
+              Math.round(xR /  -88.904 +  339.781)
+            , Math.round(yR / -121.44  +  259.707) 
+      ...
+```
+
+ */
+
+exports = // XPT2046 module - 
+{ poll: 50 // default poll interval when touched in milliseconds
+, calc: function(xRaw, yRaw, data, module) {  // default x / y
+      return [xRaw, yRaw, data, module];      // ...calculation...
+    }                                         // ... (pass thru)
+, lstn: false // is listening to touch and untouch (calling back)
+, listen:  function(lstn) {
+    this.lstn = ((lstn === undefined) || lstn);
+    return this;
+  }
+, connect: function(spi, cs, irq, callback, calc, poll) {
+    // overwrite default 'calculation' (pass thru raw values)
+    if (calc) { this.calc = calc; }
+    // overwrite default poll interval (50) in milliseconds
+    if (poll) { this.poll = poll; }
+    // wake the controller up
+    spi.send([0x90,0],cs);
+    // look for a press
+    var watchFunction = function() {
+      var interval = setInterval(function () {
+        if (!digitalRead(irq)) { // touch down
+          var data = spi.send([0x90,0,0xD0,0,0], cs);
+          if (this.lstn) {
+            callback.apply(
+                undefined
+              , this.calc(
+                    data[1]*256+data[2], data[3]*256+data[4]
+                  , data
+                  , this
+                  )
+              );
+          }
+        } else { // 'untouch'
+          clearInterval(interval);
+          interval = undefined;
+          if (this.lstn) {
+            callback(undefined, undefined, undefined, this);
+          }
+          setWatch(watchFunction, irq
+              , { repeat : false, edge: "falling" });
+        }
+      }.bind(this), this.poll); // poll interval on touch
+    }.bind(this);
+    setWatch(watchFunction, irq
+        , { repeat : false, edge: "falling" });
+    return this;
+  }
+};