151 lines
5.8 KiB
C
151 lines
5.8 KiB
C
#ifndef __ONEWIRE_H__
|
|
#define __ONEWIRE_H__
|
|
|
|
#include "c_types.h"
|
|
|
|
// 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 0
|
|
#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
|
|
|
|
// Platform specific I/O definitions
|
|
|
|
#define DIRECT_READ(pin) (0x1 & GPIO_INPUT_GET(GPIO_ID_PIN(pin_num[pin])))
|
|
#define DIRECT_MODE_INPUT(pin) GPIO_DIS_OUTPUT(pin_num[pin])
|
|
#define DIRECT_MODE_OUTPUT(pin)
|
|
#define DIRECT_WRITE_LOW(pin) (GPIO_OUTPUT_SET(GPIO_ID_PIN(pin_num[pin]), 0))
|
|
#define DIRECT_WRITE_HIGH(pin) (GPIO_OUTPUT_SET(GPIO_ID_PIN(pin_num[pin]), 1))
|
|
|
|
void onewire_init(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 onewire_reset(uint8_t pin);
|
|
|
|
// Issue a 1-Wire rom select command, you do the reset first.
|
|
void onewire_select(uint8_t pin, const uint8_t rom[8]);
|
|
|
|
// Issue a 1-Wire rom skip command, to address all on bus.
|
|
void onewire_skip(uint8_t pin);
|
|
|
|
// 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 onewire_write(uint8_t pin, uint8_t v, uint8_t power);
|
|
|
|
void onewire_write_bytes(uint8_t pin, const uint8_t *buf, uint16_t count, bool power);
|
|
|
|
// Read a byte.
|
|
uint8_t onewire_read(uint8_t pin);
|
|
|
|
void onewire_read_bytes(uint8_t pin, 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 onewire_write_bit(uint8_t pin, uint8_t v);
|
|
|
|
// Read a bit.
|
|
// uint8_t onewire_read_bit(uint8_t pin);
|
|
|
|
// 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 onewire_depower(uint8_t pin);
|
|
|
|
#if ONEWIRE_SEARCH
|
|
// Clear the search state so that if will start from the beginning again.
|
|
void onewire_reset_search(uint8_t pin);
|
|
|
|
// Setup the search to find the device type 'family_code' on the next call
|
|
// to search(*newAddr) if it is present.
|
|
void onewire_target_search(uint8_t pin, uint8_t family_code);
|
|
|
|
// 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 onewire_search(uint8_t pin, uint8_t *newAddr);
|
|
#endif
|
|
|
|
#if ONEWIRE_CRC
|
|
// Compute a Dallas Semiconductor 8 bit CRC, these are used in the
|
|
// ROM and scratchpad registers.
|
|
uint8_t onewire_crc8(const 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.
|
|
// @param crc - The crc starting value (optional)
|
|
// @return True, iff the CRC matches.
|
|
bool onewire_check_crc16(const uint8_t* input, uint16_t len, const uint8_t* inverted_crc, uint16_t 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.
|
|
// @param crc - The crc starting value (optional)
|
|
// @return The CRC16, as defined by Dallas Semiconductor.
|
|
uint16_t onewire_crc16(const uint8_t* input, uint16_t len, uint16_t crc);
|
|
#endif
|
|
#endif
|
|
|
|
#endif
|