Merge pull request #75 from mprse/io_examples

Add IO examples: SPIMaster and I2CSlave

Author: Qinghao Shi

APIs_IO/I2CSlave/README.md

@@ -0,0 +1,5 @@
+# I2C Slave example
+
+This example shows how an `I2C` responder works.
+
+**Note:** Please adapt `I2C` pins for target different than `K64F`.

APIs_IO/I2CSlave/main.cpp

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+#include <mbed.h>
+
+#if !DEVICE_I2CSLAVE
+#error [NOT_SUPPORTED] I2C Slave is not supported
+#endif
+
+I2CSlave slave(D14, D15);
+
+int main()
+{
+    char buf[10];
+    char msg[] = "Slave!";
+
+    slave.address(0xA0);
+    while (1) {
+        int i = slave.receive();
+        switch (i) {
+            case I2CSlave::ReadAddressed:
+                slave.write(msg, strlen(msg) + 1); // Includes null char
+                break;
+            case I2CSlave::WriteGeneral:
+                slave.read(buf, 10);
+                printf("Read G: %s\n", buf);
+                break;
+            case I2CSlave::WriteAddressed:
+                slave.read(buf, 10);
+                printf("Read A: %s\n", buf);
+                break;
+        }
+        for (int i = 0; i < 10; i++) {
+            buf[i] = 0;    // Clear buffer
+        }
+    }
+}

APIs_IO/SPISlave/README.md

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+# SPI Slave example
+
+This example shows how an `SPI` slave responder works.
+
+**Note:** Please adapt `SPI` pins for target different than `K64F`.

APIs_IO/SPISlave/main.cpp

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+#include "mbed.h"
+
+SPISlave device(D12, D11, D13, D10); // mosi, miso, sclk, ssel
+
+int main()
+{
+    device.reply(0x00);              // Prime SPI with first reply
+    while (1) {
+        if (device.receive()) {
+            int v = device.read();   // Read byte from master
+            v = (v + 1) % 0x100;     // Add one to it, modulo 256
+            device.reply(v);         // Make this the next reply
+        }
+    }
+}