add auto address feature

when set address to 0 in LcdInit(), it will try to get correctly address automitic.

Author: shaoziyang

README.md

@@ -20,12 +20,13 @@ to search box then search.
 ## I2C Address  
 - PCF8574: 39  
 - PCF8574A: 63  
+- Auto: 0
 
 ## API
 
 - LcdInit(Addr: number)  
 Initial LCD  
-Addr: I2C Address.  
+Addr: I2C Address. If Addr is zero, it will automatic recognition correctly address.  
 
 - ShowNumber(n: number, x: number, y: number)  
 show a number in LCD at given position.  

main.ts

@@ -1,8 +1,8 @@
 /**
- * makecode I2C LCD1602 package for microbit.
- * From microbit/micropython Chinese community.
- * http://www.micropython.org.cn
- */
+* makecode I2C LCD1602 package for microbit.
+* From microbit/micropython Chinese community.
+* http://www.micropython.org.cn
+*/
 
 /**
  * Custom blocks
@@ -42,14 +42,44 @@ namespace I2C_LCD1602 {
         set(d << 4)
     }
 
+    // auto get LCD address
+    function AutoAddr() {
+        let k = true
+        let addr = 0x20
+        let d1 = 0, d2 = 0
+        while (k && (addr < 0x28)) {
+            pins.i2cWriteNumber(addr, 0xffffffff, NumberFormat.Int32LE)
+            d1 = pins.i2cReadNumber(addr, NumberFormat.Int8LE) % 16
+            pins.i2cWriteNumber(addr, 0, NumberFormat.Int16LE)
+            d2 = pins.i2cReadNumber(addr, NumberFormat.Int8LE)
+            if ((d1 == 7) && (d2 == 0)) k = false
+            else addr += 1
+        }
+        if (!k) return addr
+
+        addr = 0x38
+        while (k && (addr < 0x40)) {
+            pins.i2cWriteNumber(addr, 0xffffffff, NumberFormat.Int32LE)
+            d1 = pins.i2cReadNumber(addr, NumberFormat.Int8LE) % 16
+            pins.i2cWriteNumber(addr, 0, NumberFormat.Int16LE)
+            d2 = pins.i2cReadNumber(addr, NumberFormat.Int8LE)
+            if ((d1 == 7) && (d2 == 0)) k = false
+            else addr += 1
+        }
+        if (!k) return addr
+        else return 0
+
+    }
+
     /**
      * initial LCD, set I2C address. Address is 39/63 for PCF8574/PCF8574A
-     * @param Addr is i2c address for LCD, eg: 39, 63
+     * @param Addr is i2c address for LCD, eg: 0, 39, 63. 0 is auto find address
      */
     //% blockId="I2C_LCD1620_SET_ADDRESS" block="LCD initialize with Address %addr"
     //% weight=100 blockGap=8
     export function LcdInit(Addr: number) {
-        i2cAddr = Addr
+        if (Addr == 0) i2cAddr = AutoAddr()
+        else i2cAddr = Addr
         BK = 8
         RS = 0
         cmd(0x33)       // set 4bit mode
@@ -168,4 +198,4 @@ namespace I2C_LCD1602 {
     export function shr(): void {
         cmd(0x1C)
     }
-}
+}

pxt.json

@@ -1,6 +1,6 @@
 {
     "name": "i2cLCD1602",
-    "version": "1.3.0",
+    "version": "1.5.0",
     "description": "makecode I2C LCD1602 package for micro:bit",
     "license": "MIT",
     "dependencies": {

test.ts

@@ -1,5 +1,5 @@
 let item = 0
-I2C_LCD1602.LcdInit(63)
+I2C_LCD1602.LcdInit(0)
 I2C_LCD1602.ShowString("Hello", 0, 0)
 basic.forever(() => {
     item += 1