Diff: spektRx.c

Revision:

0:80f1104f405a

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spektRx.c	Tue Oct 25 18:15:55 2011 +0000
@@ -0,0 +1,73 @@
+#include "mbed.h"
+#include "spektRx.h"
+
+#define NUM_CHAN (7)
+#define NUM_BYTES_IN_FRAME (2*NUM_CHAN+2)
+
+void spektRx_init(spektRx_t* self){
+    self -> state = 0;
+    self -> valid = false;
+    self -> frameNum = 0L;
+}
+
+bool spektRx_hasValidFrame(spektRx_t* self){
+    return self->valid;
+}
+
+void spektRx_runChar(spektRx_t* self, unsigned char c){
+    switch(self->state){
+        case 0: /* new frame cycle */
+            /* first preamble byte received: now expect 2nd preamble byte */
+            self->state = (c == 0x03) ? 1 : 0;
+            break;
+
+        case 1:
+            /* 2nd preamble byte received: Now expect first data byte */             
+            self->state = (c == 0x01) ? 2 : 0;
+            break;
+
+        default:
+            /* store received byte */
+            self->data[self -> state - 2] = c;
+            ++self->state;
+
+            if (self->state == NUM_BYTES_IN_FRAME){
+                /* one complete frame was received.
+                 * - Copy the data
+                 * - mask out bits 10..15
+                 */
+                int ix; 
+                for (ix = 0; ix < NUM_CHAN; ++ix){
+                    self->out[ix] = ((self->data[2*ix] & 3) << 8) | self->data[2*ix+1];
+                }
+
+                /* output data is now valid */
+                self->valid = true;
+                ++self->frameNum;
+
+                /* ready for the next frame */
+                self->state = 0;
+            } /* if frame complete */
+    } /* switch state */
+}
+
+void spektRx_runSerial(spektRx_t* self, Serial* s){
+    while(s -> readable())
+        spektRx_runChar(self, s -> getc());
+}
+
+unsigned short* spektRx_getChannelData(spektRx_t* self){
+    return (unsigned short*) self -> out;
+}
+
+float spektRx_getChannelValue(spektRx_t* self, char ixChan){
+    return (float)self->out[ixChan] / 512.0f - 1.0f;
+}
+
+long spektRx_getFrameNum(spektRx_t* self){
+    return self->frameNum;
+}
+
+void spektRx_invalidateFrame(spektRx_t* self){
+    self->valid = false;
+}