Module actuators_driver 

The C ABI for the actuator drivers that run over an I2C bus.

A PamojaPca9685 drives the PCA9685’s sixteen PWM channels over a PamojaI2cBus. It puts the oscillator to sleep, writes the prescale for its frequency, sets the output wiring, wakes the oscillator, waits the 500 us it needs, and restarts the channels; then it loads a channel’s four registers in one transfer. It holds a share of the bus, so the caller may free its own bus handle straight after building the driver, or keep it to read the part back.

pamoja_pca9685_sim_part is a PCA9685 that is not there. It holds the part’s power-on registers and keeps its datasheet’s rules, so what a driver wrote reads back off a simulated bus the way the part would hold it.

A failure is PamojaStatus::Io when the bus failed and PamojaStatus::InvalidArgument for a command the part cannot take, such as a channel past 15, with the reason in the last error message.

Structs

PamojaPca9685

A PCA9685 driver. Opaque; release it with pamoja_pca9685_free.

PamojaPca9685Outputs

How a PCA9685’s sixteen outputs are wired, the MODE2 register.

PamojaPca9685Settings

How a PCA9685 driver programs the part.

Constants

PAMOJA_PCA9685_DEFAULT_FREQUENCY_HZ

The frequency a PCA9685 driver runs at unless given another, in hertz: the part’s own power-on 200 Hz.

Functions

pamoja_pca9685_channel^⚠

Reads one channel’s counts back from the part, one register a transfer, so the read works whatever MODE1 holds and changes nothing on the part.

pamoja_pca9685_free^⚠

Releases a driver and its share of the bus. A null pointer is ignored.

pamoja_pca9685_frequency^⚠

Returns the frequency the part runs at once the prescaler has rounded the one asked for.

pamoja_pca9685_init^⚠

Puts the oscillator to sleep, writes the prescale and the output wiring, wakes it, waits the 500 us it needs, and restarts the channels.

pamoja_pca9685_new^⚠

Creates a PCA9685 driver on a bus. Nothing is sent until pamoja_pca9685_init or the first channel is loaded.

pamoja_pca9685_prescale^⚠

Returns the prescale value the driver writes for its frequency.

pamoja_pca9685_set_all^⚠

Loads every channel with the same counts in one transfer, through the ALL_LED registers.

pamoja_pca9685_set_channel^⚠

Loads one channel’s on and off counts, initializing the part first if it has not been.

pamoja_pca9685_settings_default

Returns the settings a PCA9685 driver takes when given none: 200 Hz on the internal oscillator with totem-pole outputs, the part’s own power-on state.

pamoja_pca9685_sim_part

Creates a simulated PCA9685 as it powers up: asleep at 200 Hz with every output off, keeping its datasheet’s rules for writes, reads, and its register pointer.

pamoja_pca9685_sleep^⚠

Stops the oscillator. The channel registers keep their values, and a channel still running when the part sleeps sets its RESTART bit.

pamoja_pca9685_software_reset^⚠

Sends the general-call software reset, which returns every PCA9685 on the bus to its power-on state, not only this one. It goes to address 0x00, which nothing on a simulated bus answers.

pamoja_pca9685_wake^⚠

Wakes the oscillator, waits the 500 us it needs, and restarts every channel that was running before the sleep.