Connect all Promise chains

README.md

@@ -25,9 +25,10 @@ npm i adafruit-i2c-pwm-driver
 const makePwmDriver = require('adafruit-i2c-pwm')
 const pwmDriver = makePwmDriver({address: 0x40, device: '/dev/i2c-1'})
 
-pwmDriver.setPWMFreq(50)
-pwmDriver.setPWM(2) // channel, on , off
-
+pwmDriver.init()
+  .then(() => pwmDriver.setPWMFreq(50))
+  .then(() => pwmDriver.setPWM(2))// channel, on , off
+  .catch(console.error);
 ```
 
 To configure I2c on your Raspberry-pi / Beaglebone please see [here](https://npmjs.org/package/i2c)
@@ -46,17 +47,21 @@ Setting up a new PwmDriver
 - device: Device name, e.g. '/dev/i2c-1' (defaults to /dev/i2c-1)
 - debug: flag used to display debug messages
 
+`pwmDriver.init()`
+
+Initialize the PwmDriver. Only required once after `makePwmDriver`. Returns a Promise.
+
 `pwmDriver.setPWMFreq(frequency:Number)`
 
-Set the PWM frequency to the provided value (in hertz).
+Set the PWM frequency to the provided value (in hertz). Returns a Promise.
 
 `pwmDriver.setPWM(channel:Number, on:Number, off:Number)`
 
-Sets a single PWM channel.
+Sets a single PWM channel. Returns a Promise.
 
 `pwmDriver.setALLPWM(channel:Number, on:Number, off:Number)`
 
-Sets all PWM channels.
+Sets all PWM channels. Returns a Promise.
 
 
 ## Contribute

src/index.js

@@ -64,19 +64,18 @@ function makePwmDriver (options) {
 
     // i2c.writeBytes(MODE1, 0x00)
     // in the future use await i2c.writeBytes(MODE1, ALLCALL)
-    setAllPWM(0, 0)
-    i2c.writeBytes(MODE2, OUTDRV)
-    i2c.writeBytes(MODE1, ALLCALL)
-    usleep(5000)
-      .then(x => i2c.readBytes(MODE1, 1)
-        .then((mode1) => {
-          mode1 = mode1 & ~SLEEP // wake up (reset sleep)
-          return i2c.writeBytes(MODE1, mode1)
-        })
-        .then(usleep(5000)) // wait for oscillator)
-        .then(x => debug ? console.log('init done ') : '')
-        .catch(e => console.error('error in init', e))
-    )
+
+    return setAllPWM(0, 0)
+      .then(() => i2c.writeBytes(MODE2, OUTDRV))
+      .then(() => i2c.writeBytes(MODE1, ALLCALL))
+      .then(() => usleep(5000))
+      .then(() => i2c.readBytes(MODE1, 1))
+      .then((mode1) => {
+        mode1 = mode1 & ~SLEEP // wake up (reset sleep)
+        return i2c.writeBytes(MODE1, mode1)
+      })
+      .then(() => usleep(5000)) // wait for oscillator)
+      .then(() => debug ? console.log('init done ') : '')
   }
 
   const setPWMFreq = freq => {
@@ -95,19 +94,21 @@ function makePwmDriver (options) {
       console.log(`Final pre-scale: ${prescale}`)
     }
 
+    let oldmode;
+    let newmode;
     return i2c.readBytes(MODE1, 1)
       .then(function (data) {
-        const oldmode = data[0]
-        let newmode = (oldmode & 0x7F) | 0x10 // sleep
+        oldmode = data[0]
+        newmode = (oldmode & 0x7F) | 0x10 // sleep
         if (debug) {
           console.log(`prescale ${Math.floor(prescale)}, newMode: newmode.toString(16)`)
         }
-        i2c.writeBytes(MODE1, newmode) // go to sleep
-        i2c.writeBytes(PRESCALE, Math.floor(prescale))
-        i2c.writeBytes(MODE1, oldmode)
-        usleep(5000)
-          .then(x => i2c.writeBytes(MODE1, oldmode | 0x80))
+        return i2c.writeBytes(MODE1, newmode) // go to sleep
       })
+      .then(() => i2c.writeBytes(PRESCALE, Math.floor(prescale)))
+      .then(() => i2c.writeBytes(MODE1, oldmode))
+      .then(() => usleep(5000))
+      .then(() => i2c.writeBytes(MODE1, oldmode | 0x80));
   }
 
   // Sets a single PWM channel
@@ -119,31 +120,30 @@ function makePwmDriver (options) {
     await i2c.writeBytes(LED0_ON_H + 4 * channel, on >> 8)
     await i2c.writeBytes(LED0_OFF_L + 4 * channel, off & 0xFF)
     await i2c.writeBytes(LED0_OFF_H + 4 * channel, off >> 8)*/
-    i2c.writeBytes(LED0_ON_L + 4 * channel, on & 0xFF)
-    i2c.writeBytes(LED0_ON_H + 4 * channel, on >> 8)
-    i2c.writeBytes(LED0_OFF_L + 4 * channel, off & 0xFF)
-    i2c.writeBytes(LED0_OFF_H + 4 * channel, off >> 8)
+    return i2c.writeBytes(LED0_ON_L + 4 * channel, on & 0xFF)
+      .then(() => i2c.writeBytes(LED0_ON_H + 4 * channel, on >> 8))
+      .then(() => i2c.writeBytes(LED0_OFF_L + 4 * channel, off & 0xFF))
+      .then(() => i2c.writeBytes(LED0_OFF_H + 4 * channel, off >> 8))
   }
 
   const setAllPWM = (on, off) => {
     /*await i2c.writeBytes(ALL_LED_ON_L, on & 0xFF)
     await i2c.writeBytes(ALL_LED_ON_H, on >> 8)
     await i2c.writeBytes(ALL_LED_OFF_L, off & 0xFF)
     await i2c.writeBytes(ALL_LED_OFF_H, off >> 8)*/
-    i2c.writeBytes(ALL_LED_ON_L, on & 0xFF)
-    i2c.writeBytes(ALL_LED_ON_H, on >> 8)
-    i2c.writeBytes(ALL_LED_OFF_L, off & 0xFF)
-    i2c.writeBytes(ALL_LED_OFF_H, off >> 8)
+    return i2c.writeBytes(ALL_LED_ON_L, on & 0xFF)
+      .then(() => i2c.writeBytes(ALL_LED_ON_H, on >> 8))
+      .then(() => i2c.writeBytes(ALL_LED_OFF_L, off & 0xFF))
+      .then(() => i2c.writeBytes(ALL_LED_OFF_H, off >> 8))
   }
 
   const stop = () => i2c.writeBytes(ALL_LED_OFF_H, 0x01)
 
-  // actual init
-  init()
-
   return {
+    init,
     setPWM,
     setAllPWM,
     setPWMFreq,
-  stop}
+    stop
+  }
 }