DS1Wire.cpp

00001 #include "DS1Wire.h"
00002 #include "mbed.h"
00003 #include <stdint.h>
00004 
00005 // Timing delay for 1-wire serial standard option
00006 enum DELAY { A = 6, B = 64, C = 60, D = 10, E = 9, F = 55, G = 0, H = 480, I = 70, J = 410 };
00007 
00008    
00009 int Reset(DigitalInOut& pin) {
00010     pin.output();
00011     pin = 0;    // drive bus low
00012     wait_us(H);
00013     pin.input(); // release bus
00014     wait_us(I);
00015     uint32_t result = pin;  // read bus value
00016     wait_us(J);
00017     return result;
00018 }
00019 
00020 void WriteBit(DigitalInOut& pin, uint32_t bit) {
00021     pin.output();
00022     if (bit) {
00023         pin = 0;        // drive bus low
00024         wait_us(A);        // delay A
00025         pin.input();      // release bus
00026         wait_us(B);        // delay B
00027     } else {
00028         pin = 0;    // drive bus low
00029         wait_us(C);    // delay C
00030         pin.input();  // release bus
00031         wait_us(D);    // delay D
00032     }
00033 }
00034 
00035 uint32_t ReadBit(DigitalInOut& pin) {
00036     uint32_t bit_value;
00037     pin.output();
00038     pin = 0;        // drive bus low
00039     wait_us(A);        // delay A
00040     pin.input();      // release bus
00041     wait_us(E);        // delay E
00042     bit_value  = pin;    // master sample bus
00043     wait_us(F);
00044     return bit_value;
00045 }
00046 
00047 void WriteByte(DigitalInOut& pin, uint32_t byte) {
00048     for (uint32_t bit = 0; bit < 8; ++bit) {
00049         WriteBit(pin, byte & 0x01); // lsb to msb
00050         byte >>= 1;    // right shift by 1-bit
00051     }
00052 }
00053 
00054 uint32_t ReadByte(DigitalInOut& pin) {
00055     uint32_t byte = 0;
00056     for (uint32_t bit = 0; bit < 8; ++bit) {
00057         byte |= (ReadBit(pin) << bit);    // Reads lsb to msb
00058     }
00059     return byte;
00060 }