78 lines
2.0 KiB
Python
78 lines
2.0 KiB
Python
import time
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import smbus2
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import ctypes
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from collections.abc import Iterable
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from cereal import log
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class Sensor:
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class SensorException(Exception):
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pass
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class DataNotReady(SensorException):
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pass
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def __init__(self, bus: int) -> None:
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self.bus = smbus2.SMBus(bus)
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self.source = log.SensorEventData.SensorSource.velodyne # unknown
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self.start_ts = 0.
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def __del__(self):
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self.bus.close()
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def read(self, addr: int, length: int) -> bytes:
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return bytes(self.bus.read_i2c_block_data(self.device_address, addr, length))
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def write(self, addr: int, data: int) -> None:
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self.bus.write_byte_data(self.device_address, addr, data)
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def writes(self, writes: Iterable[tuple[int, int]]) -> None:
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for addr, data in writes:
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self.write(addr, data)
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def verify_chip_id(self, address: int, expected_ids: list[int]) -> int:
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chip_id = self.read(address, 1)[0]
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assert chip_id in expected_ids
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return chip_id
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# Abstract methods that must be implemented by subclasses
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@property
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def device_address(self) -> int:
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raise NotImplementedError
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def reset(self) -> None:
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# optional.
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# not part of init due to shared registers
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pass
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def init(self) -> None:
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raise NotImplementedError
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def get_event(self, ts: int | None = None) -> log.SensorEventData:
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raise NotImplementedError
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def shutdown(self) -> None:
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raise NotImplementedError
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def is_data_valid(self) -> bool:
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if self.start_ts == 0:
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self.start_ts = time.monotonic()
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# unclear whether we need this...
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return (time.monotonic() - self.start_ts) > 0.5
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# *** helpers ***
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@staticmethod
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def wait():
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# a standard small sleep
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time.sleep(0.005)
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@staticmethod
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def parse_16bit(lsb: int, msb: int) -> int:
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return ctypes.c_int16((msb << 8) | lsb).value
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@staticmethod
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def parse_20bit(b2: int, b1: int, b0: int) -> int:
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combined = ctypes.c_uint32((b0 << 16) | (b1 << 8) | b2).value
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return ctypes.c_int32(combined).value // (1 << 4)
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