Diff: PS2KB.cpp

Revision:

0:ce15490e89e9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PS2KB.cpp	Sun Feb 27 23:34:31 2011 +0000
@@ -0,0 +1,140 @@
+/**
+ * PS/2 keyboard interface control class (Version 0.0.1)
+ *
+ * Copyright (C) 2010 Shinichiro Nakamura (CuBeatSystems)
+ * http://shinta.main.jp/
+ */
+
+#include "PS2KB.h"
+
+/**
+ * Create.
+ *
+ * @param clk_pin Clock pin.
+ * @param dat_pin Data pin.
+ */
+PS2KB::PS2KB(PinName clk_pin, PinName dat_pin)
+        : clk(clk_pin), dat(dat_pin) {
+    init_work();
+    clk.fall(this, &PS2KB::func_fall);
+    timeout = 1;
+}
+
+/**
+ * Destory.
+ */
+PS2KB::~PS2KB() {
+    wdt.detach();
+}
+
+/**
+ * Get a data from a PS/2 device.
+ *
+ * @return A data from a PS/2 device.
+ */
+int PS2KB::getc() {
+    tot.reset();
+    tot.start();
+    while (work.cStart == work.cEnd) {
+        wait_ms(1);
+        if ((timeout > 0) && (tot.read_ms() > timeout)) {
+            // printf("Timeout occured.\n");
+            return EOF;
+        }
+    }
+    tot.stop();
+
+    char c = work.buffer[work.cStart++];
+    work.cStart =  work.cStart % RINGBUFSIZ;
+
+    return c;
+}
+
+/**
+ * Set timeout.
+ *
+ * @param ms Timeout ms.
+ */
+void PS2KB::setTimeout(int ms) {
+    timeout = ms;
+}
+
+void PS2KB::func_timeout(void) {
+    work.bitcnt = 0;
+}
+
+void PS2KB::func_fall(void) {
+    int oddpar = 0;
+    /*
+     */
+    switch (work.bitcnt) {
+        case 0:
+            /*
+             * Start bit.
+             */
+            if (dat.read() != 0) {
+                // printf("Illegal start bit condition.\n");
+            }
+            work.bitcnt++;
+            break;
+        case 9:
+            /*
+             * Parity bit.
+             */
+            for (int i = 0; i < 8; i++) {
+                if ((work.buffer[work.cEnd] & (1 << i)) != 0) {
+                    oddpar++;
+                }
+            }
+            if (dat.read() == 1) {
+                oddpar++;
+            }
+            if ((oddpar % 2) != 1) {
+                // printf("Data parity error.\n");
+            }
+            work.bitcnt++;
+            break;
+        case 10:
+            /*
+             * Stop bit.
+             */
+            if (dat.read() != 1) {
+                // printf("Illegal stop bit condition.\n");
+            }
+            if (work.cStart != ((work.cEnd + 1) % RINGBUFSIZ)) {
+                work.cEnd++;
+                work.cEnd = work.cEnd % RINGBUFSIZ;
+                work.bitcnt = 0;
+            } else {
+                // printf("Buffer overrun.\n");
+            }
+            break;
+        default:
+            if ((1 <= work.bitcnt) && (work.bitcnt <= 8)) {
+                /*
+                 * data bit.
+                 */
+                if (dat.read() == 1) {
+                    work.buffer[work.cEnd] |= (1 << (work.bitcnt - 1));
+                } else {
+                    work.buffer[work.cEnd] &= ~(1 << (work.bitcnt - 1));
+                }
+                work.bitcnt++;
+            } else {
+                /*
+                 * Illegal internal state.
+                 */
+                // printf("Illegal internal state found.\n");
+                init_work();
+            }
+            break;
+    }
+    wdt.detach();
+    wdt.attach_us(this, &PS2KB::func_timeout, 250);
+}
+
+void PS2KB::init_work(void) {
+    work.bitcnt = 0;
+    work.cStart = 0;
+    work.cEnd = 0;
+}