an SPI interface the cmu pixy camera
Dependents: robotic_fish_ver_4_9_pixy UMO
pixy.cpp@0:1b99a0bee9e0, 2014-06-02 (annotated)
- Committer:
- sandwich
- Date:
- Mon Jun 02 21:02:09 2014 +0000
- Revision:
- 0:1b99a0bee9e0
- Child:
- 2:fc86438b206f
tracks a single object currently
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
sandwich | 0:1b99a0bee9e0 | 1 | #include "pixy.h" |
sandwich | 0:1b99a0bee9e0 | 2 | |
sandwich | 0:1b99a0bee9e0 | 3 | pixySPI::pixySPI(PinName mosi, PinName miso, PinName sclk, Serial* ser) |
sandwich | 0:1b99a0bee9e0 | 4 | { |
sandwich | 0:1b99a0bee9e0 | 5 | spi=new SPI(mosi,miso,sclk); //the default spi settings will work fine here |
sandwich | 0:1b99a0bee9e0 | 6 | spi->format(8,0); |
sandwich | 0:1b99a0bee9e0 | 7 | spi->frequency(100000); |
sandwich | 0:1b99a0bee9e0 | 8 | sync=0xAA55; |
sandwich | 0:1b99a0bee9e0 | 9 | debug=ser; |
sandwich | 0:1b99a0bee9e0 | 10 | } |
sandwich | 0:1b99a0bee9e0 | 11 | |
sandwich | 0:1b99a0bee9e0 | 12 | pixySPI::~pixySPI() |
sandwich | 0:1b99a0bee9e0 | 13 | { |
sandwich | 0:1b99a0bee9e0 | 14 | delete spi; |
sandwich | 0:1b99a0bee9e0 | 15 | } |
sandwich | 0:1b99a0bee9e0 | 16 | |
sandwich | 0:1b99a0bee9e0 | 17 | |
sandwich | 0:1b99a0bee9e0 | 18 | short pixySPI::readTwoBytesLSB() |
sandwich | 0:1b99a0bee9e0 | 19 | { |
sandwich | 0:1b99a0bee9e0 | 20 | short out; |
sandwich | 0:1b99a0bee9e0 | 21 | char read[2]; |
sandwich | 0:1b99a0bee9e0 | 22 | read[0]=spi->write(0x00); |
sandwich | 0:1b99a0bee9e0 | 23 | read[1]=spi->write(0x00); |
sandwich | 0:1b99a0bee9e0 | 24 | out=(((short)read[0]) << 8) | read[1]; |
sandwich | 0:1b99a0bee9e0 | 25 | return out; |
sandwich | 0:1b99a0bee9e0 | 26 | } |
sandwich | 0:1b99a0bee9e0 | 27 | |
sandwich | 0:1b99a0bee9e0 | 28 | |
sandwich | 0:1b99a0bee9e0 | 29 | //this doesn't work |
sandwich | 0:1b99a0bee9e0 | 30 | void pixySPI::readNBytes(char* buf, int num) |
sandwich | 0:1b99a0bee9e0 | 31 | { |
sandwich | 0:1b99a0bee9e0 | 32 | for (int i=0; i<num; i++) { |
sandwich | 0:1b99a0bee9e0 | 33 | char byte=spi->write(0x00); |
sandwich | 0:1b99a0bee9e0 | 34 | debug->printf("%X\n", byte); |
sandwich | 0:1b99a0bee9e0 | 35 | memcpy(buf+i, &byte, 1); |
sandwich | 0:1b99a0bee9e0 | 36 | } |
sandwich | 0:1b99a0bee9e0 | 37 | } |
sandwich | 0:1b99a0bee9e0 | 38 | |
sandwich | 0:1b99a0bee9e0 | 39 | Block pixySPI::getBlock(Serial* debug) |
sandwich | 0:1b99a0bee9e0 | 40 | { |
sandwich | 0:1b99a0bee9e0 | 41 | Block out; |
sandwich | 0:1b99a0bee9e0 | 42 | uint16_t checksum=0; |
sandwich | 0:1b99a0bee9e0 | 43 | //first we need to detect the start of a block. They all start with 0xAA55 |
sandwich | 0:1b99a0bee9e0 | 44 | 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 |
sandwich | 0:1b99a0bee9e0 | 45 | //debug->printf("looking for valid signature\n"); |
sandwich | 0:1b99a0bee9e0 | 46 | while (memcmp((char*)&sync, frame, 2)!=0) { |
sandwich | 0:1b99a0bee9e0 | 47 | frame[0]=frame[1]; //move byte down |
sandwich | 0:1b99a0bee9e0 | 48 | frame[1]=spi->write(0x00); //get next byte. |
sandwich | 0:1b99a0bee9e0 | 49 | } |
sandwich | 0:1b99a0bee9e0 | 50 | spi->write(0x00); |
sandwich | 0:1b99a0bee9e0 | 51 | //ok so we got a valid signature |
sandwich | 0:1b99a0bee9e0 | 52 | //these didn't end up working |
sandwich | 0:1b99a0bee9e0 | 53 | //readNBytes((char*)(&checksum), 2); //get the checksum |
sandwich | 0:1b99a0bee9e0 | 54 | //readNBytes((char*)(&out), sizeof(Block)); //get the rest of the data |
sandwich | 0:1b99a0bee9e0 | 55 | checksum=readTwoBytesLSB(); |
sandwich | 0:1b99a0bee9e0 | 56 | out.signature=readTwoBytesLSB(); |
sandwich | 0:1b99a0bee9e0 | 57 | out.x=readTwoBytesLSB(); |
sandwich | 0:1b99a0bee9e0 | 58 | out.y=readTwoBytesLSB(); |
sandwich | 0:1b99a0bee9e0 | 59 | out.width=readTwoBytesLSB(); |
sandwich | 0:1b99a0bee9e0 | 60 | out.height=readTwoBytesLSB(); |
sandwich | 0:1b99a0bee9e0 | 61 | |
sandwich | 0:1b99a0bee9e0 | 62 | if (checksum!=(out.x+out.y+out.signature+out.width+out.height)) { |
sandwich | 0:1b99a0bee9e0 | 63 | //debug->printf("checksum doesn't add up %d\n", checksum); |
sandwich | 0:1b99a0bee9e0 | 64 | out.signature=20; //used for invalid signatures |
sandwich | 0:1b99a0bee9e0 | 65 | } |
sandwich | 0:1b99a0bee9e0 | 66 | return out; |
sandwich | 0:1b99a0bee9e0 | 67 | } |
sandwich | 0:1b99a0bee9e0 | 68 | |
sandwich | 0:1b99a0bee9e0 | 69 | char pixySPI::getRawData() |
sandwich | 0:1b99a0bee9e0 | 70 | { |
sandwich | 0:1b99a0bee9e0 | 71 | return spi->write(0x00); |
sandwich | 0:1b99a0bee9e0 | 72 | } |