I2C Server
I2C Server wraps Circuits.I2C
reference in a GenServer
, creating a separate
process for each I2C device. I2C device processes are
identified with a composite key of bus name and bus address. By default, I2C device 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, "~> 0.1"}
]
end
Usage
# Get a PID for a device at the address 0x77 on the "i2c-1" bus
iex> device1 = I2cServer.server_process("i2c-1", 0x77)
#PID<0.233.0>
# A different device has a different PID
iex> device2 = I2cServer.server_process("i2c-1", 0x38)
#PID<0.239.0>
# 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 device processes will be created under I2cServer.I2cDeviceSupervisor
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,
registry_module: I2cServer.DeviceRegistry
Registry module
The default :registry_module
is I2cServer.DeviceRegistry
that is a thin wrapper of Registry
.
You can alternatively use :global
for global registration.
config :i2c_server, registry_module: :global
I2C module
The default :transport_module
is Circuits.I2C
. You will most likely use the default, but you
may want to use a mock for testing. Any module that implements the I2cServer.Transport
behaviour
should work.
config :i2c_server, transport_module: Circuits.I2C