Provides a I2CBus that can be use for abstracting bus managment from device setup and configurations.
(see this example to see the non-bus style functional interaction for manual bus managment)
Given the following setup using 'i2c-bus` as our source bus implementation.
// see the standard tca9548a setup process
const { i2c, bus1, tcaDevice } = await allTheNormalSetupStuff(busNumber, busAddress)Similar to the import of a source library, the factory from method can be used to createa a bus provider.
const provider = await I2CTca9548BusFactory.from(provider, multiplexer, manager)A provider (an interface of I2CBus) has the common openPromisified call. And then can be use in a similar manaer as a native provider.
const channelAsBusNumber = 1
const vbus1 = await provider.openPromisified(channelAsBusNumber)
const abus = await I2CAddressedBus.from(vbus1, someDeviceAddress)
const device = await FictionalDevice.from(abus)
// device.read() etc ...The useage of the Channel number as the busNumber parameter in the openPromisified call creates the virtual bus numbering of the provider instance.
Extending this to a set of multi-plexed devices with overlaping bus addresses the following can be construted:
const vbus1 = // from above
const commonBusAddress = 0x77
const devices = awaitAll [0, 1, 2].map(async channel =>
FictionalDevice.from(I2CAddressedBus.from(provider.oopenPromisified(channel), commonBusAddress))
)The above code constructs a set of three FictionalDevices that share a common bus address that would otherwise not work on a single bus segment. By using the virtual bus as above the resulting devices can be used transparent to the bus configuration.
Thus the following:
cosnt d2 = await devices[2].readData()
const d0 = await devcies[0].readData()Results in the ChannelManager coordinating the device state. Thus, in the most simple case, the ChannelManager could simple call setChannel() during its before hook, cuase devices fictional readData to be read in context for both the above cases.
This simple abstraction simplifies complex layouts without application developer needing to re-factor setup and managment code.