atomvm_gleam/i2c

Typed wrappers for AtomVM 0.7 i2c.

Upstream: libs/avm_esp32/src/i2c.erl (same export names on RP2/STM32 under avm_rp2 / avm_stm32).

Two write styles

Register write — write_bytes/4 (and read_bytes/4) are one-shot transactions: they address a device, send a register/pointer byte, then write or read a payload. Do not wrap them in begin_transmission / end_transmission.

Transmission framing — begin_transmission → write_byte / write_transmission_bytes → end_transmission builds a multi-byte write by hand (useful when the first byte is not a simple register pointer, or when streaming several bytes in one stop-bit-framed message). write_bytes_to is the one-shot address+payload write without a register byte (upstream i2c:write_bytes/3); also not framed.

Types

Bus

</>

Opaque handle for an AtomVM I²C bus opened via i2c:open/1.

See i2c.erl.

pub type Bus

Config

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Bus open options. clock_speed_hz is required on AtomVM.

See i2c:open/1.

pub type Config {
  Config(scl: Int, sda: Int, clock_speed_hz: Int)
}

Constructors

Config(scl: Int, sda: Int, clock_speed_hz: Int)

Error

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Errors from the AtomVM i2c driver.

See i2c.erl.

pub type Error {
  Failed
  NotSupported
  Badarg
  Timeout
  Other(String)
}

Constructors

```
Failed
```
```
NotSupported
```
```
Badarg
```
```
Timeout
```
```
Other(String)
```

Values

begin_transmission

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pub fn begin_transmission(
  bus: Bus,
  address: Int,
) -> Result(Nil, Error)

Begin a framed write to address.

Follow with one or more write_byte / write_transmission_bytes calls, then end_transmission. Not used with register write_bytes / read_bytes.

See i2c:begin_transmission/2.

close

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pub fn close(bus: Bus) -> Result(Nil, Error)

Close an I²C bus.

See i2c:close/1.

end_transmission

</>

pub fn end_transmission(bus: Bus) -> Result(Nil, Error)

End a framed write started with begin_transmission.

See i2c:end_transmission/1.

error_to_string

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pub fn error_to_string(error: Error) -> String

Format an Error for logging.

open

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pub fn open(config: Config) -> Result(Bus, Error)

Open an I²C bus.

See i2c:open/1.

read_bytes

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pub fn read_bytes(
  bus: Bus,
  address: Int,
  register: Int,
  count: Int,
) -> Result(BitArray, Error)

Read count bytes from address at register (pointer byte).

One-shot; do not wrap in begin_transmission / end_transmission.

See i2c:read_bytes/4.

write_byte

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pub fn write_byte(bus: Bus, byte: Int) -> Result(Nil, Error)

Queue one byte inside an open transmission (begin_transmission … end_transmission).

See i2c:write_byte/2.

write_bytes

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pub fn write_bytes(
  bus: Bus,
  address: Int,
  register: Int,
  data: BitArray,
) -> Result(Nil, Error)

Write data to address at register (pointer byte).

One-shot register write (upstream i2c:write_bytes/4). Do not wrap in begin_transmission / end_transmission; use those helpers when you need a custom framed payload instead.

See i2c:write_bytes/4.

write_bytes_to

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pub fn write_bytes_to(
  bus: Bus,
  address: Int,
  data: BitArray,
) -> Result(Nil, Error)

Write data to address (no register pointer byte).

Upstream i2c:write_bytes/3. One-shot; do not wrap in transmission helpers.

See i2c:write_bytes/3.

write_transmission_bytes

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pub fn write_transmission_bytes(
  bus: Bus,
  data: BitArray,
) -> Result(Nil, Error)

Queue a byte sequence inside an open transmission.

Upstream i2c:write_bytes/2.

See i2c:write_bytes/2.