I2C Server
I2C Server wraps Circuits.I2C
reference in a GenServer
, creating a separate
process per I2C bus. I2C bus processes are
identified with a bus name (e.g., "i2c-1"
). By default, I2C bus processes are
stored in Registry
, but you can alternatively use
:global
.
Installation
Just add i2c_server
to your list of dependencies in mix.exs
:
def deps do
[
{:i2c_server, "~> 0.2"}
]
end
Usage
# Get a PID for the "i2c-1" bus
iex> {:ok, device1} = I2cServer.start_link(bus_name: "i2c-1", bus_address: 0x77)
#PID<0.233.0>
# Write 0xff to the register 0x8A
iex> I2cServer.write(device1, 0x8A, 0xff)
iex> I2cServer.write(device1, 0x8A, <<0xff>>)
iex> I2cServer.write(device1, <<0x8A, 0xff>>)
iex> I2cServer.write(device1, [0x8A, 0xff])
iex> I2cServer.write(device1, [0x8A, <<0xff>>])
:ok
# Read 3 bytes from the register 0xE1
iex> I2cServer.write_read(device1, 0xE1, 3)
iex> I2cServer.write_read(device1, <<0xE1>>, 3)
{:ok, <<0, 0, 0>>}
I2C bus processes will be created under I2cServer.I2cBusSupervisor
dynamically.
Configuration
You can change settings in your config file such as config/config.exs
file. Here is the default
configuration.
config :i2c_server,
transport_module: Circuits.I2C,
bus_registry_module: I2cServer.BusRegistry
Registry module
The default :bus_registry_module
is I2cServer.BusRegistry
that is a thin wrapper of Registry
.
You can alternatively use :global
for global registration.
config :i2c_server,
bus_registry_module: :global
Transport module
The default :transport_module
is Circuits.I2C
. You will most likely use the default, but you
may want to replace it with a mock for testing.
config :i2c_server,
transport_module: MyApp.MockTransport