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#ifndef OneWire_h
#define OneWire_h
#include <inttypes.h>
#if ARDUINO >= 100
#include "Arduino.h" // for delayMicroseconds, digitalPinToBitMask, etc
#else
#include "WProgram.h" // for delayMicroseconds
#include "pins_arduino.h" // for digitalPinToBitMask, etc
#endif
// You can exclude certain features from OneWire. In theory, this
// might save some space. In practice, the compiler automatically
// removes unused code (technically, the linker, using -fdata-sections
// and -ffunction-sections when compiling, and Wl,--gc-sections
// when linking), so most of these will not result in any code size
// reduction. Well, unless you try to use the missing features
// and redesign your program to not need them! ONEWIRE_CRC8_TABLE
// is the exception, because it selects a fast but large algorithm
// or a small but slow algorithm.
// you can exclude onewire_search by defining that to 0
#ifndef ONEWIRE_SEARCH
#define ONEWIRE_SEARCH 1
#endif
// You can exclude CRC checks altogether by defining this to 0
#ifndef ONEWIRE_CRC
#define ONEWIRE_CRC 1
#endif
// Select the table-lookup method of computing the 8-bit CRC
// by setting this to 1. The lookup table enlarges code size by
// about 250 bytes. It does NOT consume RAM (but did in very
// old versions of OneWire). If you disable this, a slower
// but very compact algorithm is used.
#ifndef ONEWIRE_CRC8_TABLE
#define ONEWIRE_CRC8_TABLE 1
#endif
// You can allow 16-bit CRC checks by defining this to 1
// (Note that ONEWIRE_CRC must also be 1.)
#ifndef ONEWIRE_CRC16
#define ONEWIRE_CRC16 1
#endif
#define FALSE 0
#define TRUE 1
// Platform specific I/O definitions
#if defined(__AVR__)
#define PIN_TO_BASEREG(pin) (portInputRegister(digitalPinToPort(pin)))
#define PIN_TO_BITMASK(pin) (digitalPinToBitMask(pin))
#define IO_REG_TYPE uint8_t
#define IO_REG_ASM asm("r30")
#define DIRECT_READ(base, mask) (((*(base)) & (mask)) ? 1 : 0)
#define DIRECT_MODE_INPUT(base, mask) ((*(base+1)) &= ~(mask))
#define DIRECT_MODE_OUTPUT(base, mask) ((*(base+1)) |= (mask))
#define DIRECT_WRITE_LOW(base, mask) ((*(base+2)) &= ~(mask))
#define DIRECT_WRITE_HIGH(base, mask) ((*(base+2)) |= (mask))
#elif defined(__PIC32MX__)
#include <plib.h> // is this necessary?
#define PIN_TO_BASEREG(pin) (portModeRegister(digitalPinToPort(pin)))
#define PIN_TO_BITMASK(pin) (digitalPinToBitMask(pin))
#define IO_REG_TYPE uint32_t
#define IO_REG_ASM
#define DIRECT_READ(base, mask) (((*(base+4)) & (mask)) ? 1 : 0) //PORTX + 0x10
#define DIRECT_MODE_INPUT(base, mask) ((*(base+2)) = (mask)) //TRISXSET + 0x08
#define DIRECT_MODE_OUTPUT(base, mask) ((*(base+1)) = (mask)) //TRISXCLR + 0x04
#define DIRECT_WRITE_LOW(base, mask) ((*(base+8+1)) = (mask)) //LATXCLR + 0x24
#define DIRECT_WRITE_HIGH(base, mask) ((*(base+8+2)) = (mask)) //LATXSET + 0x28
#else
#error "Please define I/O register types here"
#endif
class OneWire
{
private:
IO_REG_TYPE bitmask;
volatile IO_REG_TYPE *baseReg;
#if ONEWIRE_SEARCH
// global search state
unsigned char ROM_NO[8];
uint8_t LastDiscrepancy;
uint8_t LastFamilyDiscrepancy;
uint8_t LastDeviceFlag;
#endif
public:
OneWire( uint8_t pin);
// Perform a 1-Wire reset cycle. Returns 1 if a device responds
// with a presence pulse. Returns 0 if there is no device or the
// bus is shorted or otherwise held low for more than 250uS
uint8_t reset(void);
// Issue a 1-Wire rom select command, you do the reset first.
void select( uint8_t rom[8]);
// Issue a 1-Wire rom skip command, to address all on bus.
void skip(void);
// Write a byte. If 'power' is one then the wire is held high at
// the end for parasitically powered devices. You are responsible
// for eventually depowering it by calling depower() or doing
// another read or write.
void write(uint8_t v, uint8_t power = 0);
void write_bytes(const uint8_t *buf, uint16_t count, bool power = 0);
// Read a byte.
uint8_t read(void);
void read_bytes(uint8_t *buf, uint16_t count);
// Write a bit. The bus is always left powered at the end, see
// note in write() about that.
void write_bit(uint8_t v);
// Read a bit.
uint8_t read_bit(void);
// Stop forcing power onto the bus. You only need to do this if
// you used the 'power' flag to write() or used a write_bit() call
// and aren't about to do another read or write. You would rather
// not leave this powered if you don't have to, just in case
// someone shorts your bus.
void depower(void);
#if ONEWIRE_SEARCH
// Clear the search state so that if will start from the beginning again.
void reset_search();
// Look for the next device. Returns 1 if a new address has been
// returned. A zero might mean that the bus is shorted, there are
// no devices, or you have already retrieved all of them. It
// might be a good idea to check the CRC to make sure you didn't
// get garbage. The order is deterministic. You will always get
// the same devices in the same order.
uint8_t search(uint8_t *newAddr);
#endif
#if ONEWIRE_CRC
// Compute a Dallas Semiconductor 8 bit CRC, these are used in the
// ROM and scratchpad registers.
static uint8_t crc8( uint8_t *addr, uint8_t len);
#if ONEWIRE_CRC16
// Compute the 1-Wire CRC16 and compare it against the received CRC.
// Example usage (reading a DS2408):
// // Put everything in a buffer so we can compute the CRC easily.
// uint8_t buf[13];
// buf[0] = 0xF0; // Read PIO Registers
// buf[1] = 0x88; // LSB address
// buf[2] = 0x00; // MSB address
// WriteBytes(net, buf, 3); // Write 3 cmd bytes
// ReadBytes(net, buf+3, 10); // Read 6 data bytes, 2 0xFF, 2 CRC16
// if (!CheckCRC16(buf, 11, &buf[11])) {
// // Handle error.
// }
//
// @param input - Array of bytes to checksum.
// @param len - How many bytes to use.
// @param inverted_crc - The two CRC16 bytes in the received data.
// This should just point into the received data,
// *not* at a 16-bit integer.
// @return True, iff the CRC matches.
static bool check_crc16(uint8_t* input, uint16_t len, uint8_t* inverted_crc);
// Compute a Dallas Semiconductor 16 bit CRC. This is required to check
// the integrity of data received from many 1-Wire devices. Note that the
// CRC computed here is *not* what you'll get from the 1-Wire network,
// for two reasons:
// 1) The CRC is transmitted bitwise inverted.
// 2) Depending on the endian-ness of your processor, the binary
// representation of the two-byte return value may have a different
// byte order than the two bytes you get from 1-Wire.
// @param input - Array of bytes to checksum.
// @param len - How many bytes to use.
// @return The CRC16, as defined by Dallas Semiconductor.
static uint16_t crc16(uint8_t* input, uint16_t len);
#endif
#endif
};
#endif