Multiple cleanups/tweaks for onewire driver
Use onewire_addr_t for onewire addresses Move internal defines out of onewire.h Remove global variables for search state use taskENTER_CRITICAL instead of portDISABLE_INTERRUPTS remove unnecessary onewire_init function Remove unnecessary critical sections Use GPIO_OUT_OPEN_DRAIN reformat/style cleanup
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Alex Stewart
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02c35d8a71
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4 changed files with 304 additions and 359 deletions
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@ -29,75 +29,72 @@
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#define ONEWIRE_CRC8_TABLE 0
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#endif
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// Platform specific I/O definitions
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#define noInterrupts portDISABLE_INTERRUPTS
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#define interrupts portENABLE_INTERRUPTS
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#define delayMicroseconds sdk_os_delay_us
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typedef uint64_t onewire_addr_t;
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#define DIRECT_READ(pin) gpio_read(pin)
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#define DIRECT_MODE_INPUT(pin) gpio_enable(pin, GPIO_INPUT)
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#define DIRECT_MODE_OUTPUT(pin) gpio_enable(pin, GPIO_OUTPUT)
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#define DIRECT_WRITE_LOW(pin) gpio_write(pin, 0)
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#define DIRECT_WRITE_HIGH(pin) gpio_write(pin, 1)
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typedef struct {
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uint8_t rom_no[8];
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uint8_t last_discrepancy;
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bool last_device_found;
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} onewire_search_t;
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void onewire_init(uint8_t pin);
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// The following is an invalid ROM address that will never occur in a device
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// (CRC mismatch), and so can be useful as an indicator for "no-such-device",
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// etc.
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#define ONEWIRE_NONE ((onewire_addr_t)(0xffffffffffffffffLL))
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// Perform a 1-Wire reset cycle. Returns 1 if a device responds
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// with a presence pulse. Returns 0 if there is no device or the
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// bus is shorted or otherwise held low for more than 250uS
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uint8_t onewire_reset(uint8_t pin);
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bool onewire_reset(int pin);
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// Issue a 1-Wire rom select command, you do the reset first.
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void onewire_select(uint8_t pin, const uint8_t rom[8]);
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void onewire_select(int pin, const onewire_addr_t rom);
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// Issue a 1-Wire rom skip command, to address all on bus.
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void onewire_skip(uint8_t pin);
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void onewire_skip_rom(int pin);
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// Write a byte. If 'power' is one then the wire is held high at
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// the end for parasitically powered devices. You are responsible
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// for eventually depowering it by calling depower() or doing
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// another read or write.
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void onewire_write(uint8_t pin, uint8_t v, uint8_t power);
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// Write a byte. The writing code uses open-drain mode and expects the pullup
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// resistor to pull the line high when not driven low. If you need strong
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// power after the write (e.g. DS18B20 in parasite power mode) then call
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// onewire_power() after this is complete to actively drive the line high.
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void onewire_write(int pin, uint8_t v);
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void onewire_write_bytes(uint8_t pin, const uint8_t *buf, uint16_t count, bool power);
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void onewire_write_bytes(int pin, const uint8_t *buf, size_t count);
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// Read a byte.
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uint8_t onewire_read(uint8_t pin);
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uint8_t onewire_read(int pin);
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void onewire_read_bytes(uint8_t pin, uint8_t *buf, uint16_t count);
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void onewire_read_bytes(int pin, uint8_t *buf, size_t count);
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// Write a bit. The bus is always left powered at the end, see
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// note in write() about that.
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// void onewire_write_bit(uint8_t pin, uint8_t v);
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// Read a bit.
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// uint8_t onewire_read_bit(uint8_t pin);
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// Actively drive the bus high to provide extra power for certain operations of
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// parasitically-powered devices.
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void onewire_power(int pin);
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// Stop forcing power onto the bus. You only need to do this if
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// you used the 'power' flag to write() or used a write_bit() call
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// and aren't about to do another read or write. You would rather
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// not leave this powered if you don't have to, just in case
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// someone shorts your bus.
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void onewire_depower(uint8_t pin);
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// you previously called onewire_power() to drive the bus high and now want to
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// allow it to float instead. Note that onewire_reset() will also
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// automatically depower the bus first, so you do not need to call this first
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// if you just want to start a new operation.
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void onewire_depower(int pin);
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// Clear the search state so that if will start from the beginning again.
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void onewire_reset_search(uint8_t pin);
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void onewire_search_start(onewire_search_t *search);
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// Setup the search to find the device type 'family_code' on the next call
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// to search(*newAddr) if it is present.
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void onewire_target_search(uint8_t pin, uint8_t family_code);
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void onewire_search_prefix(onewire_search_t *search, uint8_t family_code);
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// Look for the next device. Returns 1 if a new address has been
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// returned. A zero might mean that the bus is shorted, there are
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// no devices, or you have already retrieved all of them. It
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// might be a good idea to check the CRC to make sure you didn't
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// get garbage. The order is deterministic. You will always get
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// the same devices in the same order.
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uint8_t onewire_search(uint8_t pin, uint8_t *newAddr);
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// Look for the next device. Returns the address of the next device on the bus,
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// or ONEWIRE_NONE if there is no next address. ONEWIRE_NONE might mean that
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// the bus is shorted, there are no devices, or you have already retrieved all
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// of them. It might be a good idea to check the CRC to make sure you didn't
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// get garbage. The order is deterministic. You will always get the same
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// devices in the same order.
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onewire_addr_t onewire_search_next(onewire_search_t *search, int pin);
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// Compute a Dallas Semiconductor 8 bit CRC, these are used in the
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// ROM and scratchpad registers.
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uint8_t onewire_crc8(const uint8_t *addr, uint8_t len);
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uint8_t onewire_crc8(const uint8_t *data, uint8_t len);
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// Compute the 1-Wire CRC16 and compare it against the received CRC.
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// Example usage (reading a DS2408):
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@ -117,9 +114,9 @@ uint8_t onewire_crc8(const uint8_t *addr, uint8_t len);
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// @param inverted_crc - The two CRC16 bytes in the received data.
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// This should just point into the received data,
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// *not* at a 16-bit integer.
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// @param crc - The crc starting value (optional)
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// @param crc_iv - The crc starting value (optional)
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// @return True, iff the CRC matches.
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bool onewire_check_crc16(const uint8_t* input, uint16_t len, const uint8_t* inverted_crc, uint16_t crc);
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bool onewire_check_crc16(const uint8_t* input, size_t len, const uint8_t* inverted_crc, uint16_t crc_iv);
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// Compute a Dallas Semiconductor 16 bit CRC. This is required to check
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// the integrity of data received from many 1-Wire devices. Note that the
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@ -131,8 +128,8 @@ bool onewire_check_crc16(const uint8_t* input, uint16_t len, const uint8_t* inve
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// byte order than the two bytes you get from 1-Wire.
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// @param input - Array of bytes to checksum.
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// @param len - How many bytes to use.
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// @param crc - The crc starting value (optional)
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// @param crc_iv - The crc starting value (optional)
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// @return The CRC16, as defined by Dallas Semiconductor.
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uint16_t onewire_crc16(const uint8_t* input, uint16_t len, uint16_t crc);
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uint16_t onewire_crc16(const uint8_t* input, size_t len, uint16_t crc_iv);
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#endif
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