-spec bus_reset() -> nothing_present | presence_detected | short_detected.

Reset the bus and check the register for devices.

This function can only be used inside of a transaction/1 call.

Return Value Description

Command code: b4h.

-spec detect() -> ok.

Reset device and activate active pullup (APU).

This function can only be used inside of a transaction/1 call.

See also: reset/0, write_config/1.

Read one data byte from the 1-Wire line.

This function can only be used inside of a transaction/1 call.

Command codes: 96h, e1h

-spec reset() -> ok.

Reset the 1-Wire Master and terminate any ongoing 1-Wire communication.

This function can only be used inside of a transaction/1 call.

Command code: f0h.

-spec search() -> fail | nothing_present | short_detected | [[byte()]].

Search the bus for devices.

This function can only be used inside of a transaction/1 call.

If there are connected devices, i.e., bus_reset/0 returns presence_detected, this function provides a list of the unique 64-bit addresses of all detected devices. Otherwise, the return values match the values from bus_reset/0 or fail for other failures during the search. The addresses are represented as lists of eight byte values.

Example

With five DS18B20 temperature sensors connected one can list the five device IDs:

 1> grisp_onewire:transaction(fun grisp_onewire:search/0).
 [[40,255,203,173,80,23,4,182],
 [40,255,67,77,96,23,5,138],
 [40,255,190,25,96,23,3,203],
 [40,255,54,42,96,23,5,35],
 [40,255,18,91,96,23,3,62]]copy

-spec transaction(fun()) -> any().

Run a 1-Wire transaction.

Use this function to make sure that there is only one process running on the 1-Wire.

Example

 2> grisp_onewire:transaction(fun() ->
                                 presence_detected = grisp_onewire:bus_reset(),
                                 grisp_onewire:write_byte(16#cc)
                              end).
 okcopy

-spec write_byte(integer()) -> ok.

Write one data byte to the 1-Wire line.

This function can only be used inside of a transaction/1 call.

Command code: a5h_

-spec write_config([apu | overdrive | spu] | integer()) -> ok.

Write configuration into 1-Wire master register.

This function can only be used inside of a transaction/1 call.

The default configuration is 0, i.e., all three configurable bits set to 0. This corresponds to an empty list. Each atom in the list activates the corresponding configuration (sets the bit to 1) and each atom not present in the list leads to a deactivation (sets the bit to 0).

Atom to Integer to Configuration Bit Mapping

Example

To activate active pullup and overdrive speed use:

 3> grisp_onewire:transaction(fun() -> grisp_onewire:write_config([apu, overdrive]) end).
 okcopy

This is the same as:

 4> grisp_onewire:transaction(fun() -> grisp_onewire:write_config(1 bor 8) end).
 okcopy

Command code: d2h.