Add readme to i2c fram module

libs/i2c-fram/README.md

@@ -0,0 +1,30 @@
+# I2C FRAM driver
+
+This library provides a driver for this FRAM part: https://www.adafruit.com/products/1895
+
+The memory is accessed one byte at a time. The library provides a utility functions
+to write an entire buffer.
+
+## Reading/writing byte
+
+```
+let addr = 100
+i2c_fram.writeByte(addr, 42)
+let val = i2c_fram.readByte(addr)
+console.log(`${addr}: ${val}`)
+```
+
+## Reading/writing a buffer
+
+This code will log current time and acceleration in X axis every second.
+
+```
+let bufSz = 8
+for (let addr = 0; addr < 0x8000; addr += bufSz) {
+    let buf = pins.createBuffer(bufSz)
+    buf.setNumber(NumberFormat.Int32LE, 0, input.runningTime())
+    buf.setNumber(NumberFormat.Int32LE, 4, input.acceleration(Dimension.X))
+    i2c_fram.writeBuffer(addr, buf)
+    basic.pause(1000)
+}
+```

libs/i2c-fram/ftest.ts

@@ -12,3 +12,5 @@ i2c_fram.writeBuffer(98, toBuf([1,2,3,4,5,6,7]))
 
 console.log("100:" + i2c_fram.readByte(100))
 console.log("101:" + i2c_fram.readByte(101))
+
+

libs/i2c-fram/kind.json

@@ -2,6 +2,7 @@
     "name": "i2c-fram",
     "description": "AdaFruit I2C FRAM driver for micro:bit",
     "files": [
+        "README.md",
         "fram.ts"
     ],
     "testFiles": [