/// Reads what a coil is currently set to. Coils are the single bit equivalent of the holding
/// registers, which is how the bypass relay reports and takes its position
pub const READ_COILS: u8 = 0x01;

pub const READ_HOLDING_REGISTERS: u8 = 0x03;

pub const READ_INPUT_REGISTERS: u8 = 0x04;

/// Drives a single coil. The value is not a zero or a one: modbus spells the two positions
/// `0xFF00` and `0x0000`, and nothing else is allowed
pub const WRITE_SINGLE_COIL: u8 = 0x05;

pub const WRITE_SINGLE_REGISTER: u8 = 0x06;

/// A device reports an error by responding with the function code of the request and this bit set
pub const EXCEPTION_MASK: u8 = 0x80;