Diff: pixy.cpp

Revision:

0:1b99a0bee9e0

Child:

2:fc86438b206f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pixy.cpp	Mon Jun 02 21:02:09 2014 +0000
@@ -0,0 +1,72 @@
+#include "pixy.h"
+
+pixySPI::pixySPI(PinName mosi, PinName miso, PinName sclk, Serial* ser)
+{
+    spi=new SPI(mosi,miso,sclk); //the default spi settings will work fine here
+    spi->format(8,0);
+    spi->frequency(100000);
+    sync=0xAA55;
+    debug=ser;
+}
+
+pixySPI::~pixySPI()
+{
+    delete spi;
+}
+
+
+short pixySPI::readTwoBytesLSB()
+{
+    short out;
+    char read[2];
+    read[0]=spi->write(0x00);
+    read[1]=spi->write(0x00);
+    out=(((short)read[0]) << 8) | read[1];
+    return out;
+}
+
+
+//this doesn't work
+void pixySPI::readNBytes(char* buf, int num)
+{
+    for (int i=0; i<num; i++) {
+        char byte=spi->write(0x00);
+        debug->printf("%X\n", byte);
+        memcpy(buf+i, &byte, 1);
+    }
+}
+
+Block pixySPI::getBlock(Serial* debug)
+{
+    Block out;
+    uint16_t checksum=0;
+    //first we need to detect the start of a block. They all start with 0xAA55
+    char frame[2]= {0,0}; //this is a 2 byte running frame of what is being recieved. It's like a first-in-last-out queue
+    //debug->printf("looking for valid signature\n");
+    while (memcmp((char*)&sync, frame, 2)!=0) {
+        frame[0]=frame[1]; //move byte down
+        frame[1]=spi->write(0x00); //get next byte.
+    }
+    spi->write(0x00);
+    //ok so we got a valid signature
+    //these didn't end up working
+    //readNBytes((char*)(&checksum), 2); //get the checksum
+    //readNBytes((char*)(&out), sizeof(Block)); //get the rest of the data
+    checksum=readTwoBytesLSB();
+    out.signature=readTwoBytesLSB();
+    out.x=readTwoBytesLSB();
+    out.y=readTwoBytesLSB();
+    out.width=readTwoBytesLSB();
+    out.height=readTwoBytesLSB();
+    
+    if (checksum!=(out.x+out.y+out.signature+out.width+out.height)) {
+        //debug->printf("checksum doesn't add up %d\n", checksum);
+        out.signature=20; //used for invalid signatures
+    }
+    return out;
+}
+
+char pixySPI::getRawData()
+{
+    return spi->write(0x00);
+}
\ No newline at end of file