src/busio.py

   1 from adafruit_blinka import Enum, Lockable, agnostic
   2
   3 class I2C(Lockable):
   4     def __init__(self, scl, sda, frequency=400000):
   5         self.init(scl, sda, frequency)
   6
   7     def init(self, scl, sda, frequency):
   8         self.deinit()
   9         from machine import I2C as _I2C
  10         from microcontroller.pin import i2cPorts
  11         for portId, portScl, portSda in i2cPorts:
  12             if scl == portScl and sda == portSda:
  13                 self._i2c = I2C(portId, mode=_I2C.MASTER, baudrate=frequency)
  14                 break
  15         else:
  16             raise NotImplementedError("No Hardware I2C on (scl,sda)={}\nValid UART ports".format(
  17         (scl, sda), i2cPorts))
  18
  19     def deinit(self):
  20         try:
  21             del self._i2c
  22         except AttributeError:
  23             pass
  24
  25     def __enter__(self):
  26         return self
  27
  28     def __exit__(self, exc_type, exc_value, traceback):
  29         self.deinit()
  30
  31     def scan(self):
  32         return self._i2c.scan()
  33
  34     def readfrom_into(self, address, buffer, start=0, end=None):
  35         if start is not 0 or end is not None:
  36             if end is None:
  37                 end = len(buffer)
  38             buffer = memoryview(buffer)[start:end]
  39         stop = True  # remove for efficiency later
  40         return self._i2c.readfrom_into(address, buffer, stop)
  41
  42     def writeto(self, address, buffer, start=0, end=None, stop=True):
  43         if start is not 0 or end is not None:
  44             if end is None:
  45                 return self._i2c.writeto(address, memoryview(buffer)[start:], stop)
  46             else:
  47                 return self._i2c.writeto(address, memoryview(buffer)[start:end], stop)
  48         return self._i2c.writeto(address, buffer, stop)
  49
  50
  51 class SPI(Lockable):
  52     def __init__(self, clock, MOSI=None, MISO=None):
  53         from microcontroller.pin import spiPorts
  54         for portId, portSck, portMosi, portMiso in spiPorts:
  55             if clock == portSck and MOSI == portMosi and MISO == portMiso:
  56                 self._spi = SPI(portId)
  57                 self._pins = (portSck, portMosi, portMiso)
  58                 break
  59         else:
  60             raise NotImplementedError(
  61                 "No Hardware SPI on (clock, MOSI, MISO)={}\nValid SPI ports:{}".
  62                 format((clock, MOSI, MISO), spiPorts))
  63
  64     def configure(self, baudrate=100000, polarity=0, phase=0, bits=8):
  65         if self._locked:
  66             from machine import Pin
  67             # TODO check if #init ignores MOSI=None rather than unsetting, to save _pinIds attribute
  68             self._spi.init(
  69                 baudrate=baudrate,
  70                 polarity=polarity,
  71                 phase=phase,
  72                 bits=bits,
  73                 firstbit=SPI.MSB,
  74                 sck=Pin(self._pins[0].id),
  75                 mosi=Pin(self._pins[1].id),
  76                 miso=Pin(self._pins[2].id)
  77             )
  78         else:
  79             raise RuntimeError("First call try_lock()")
  80
  81     def deinit(self):
  82         self._spi = None
  83         self._pinIds = None
  84
  85     def write(self, buf):
  86         return self._spi.write(buf)
  87
  88     def readinto(self, buf):
  89         return self.readinto(buf)
  90
  91     def write_readinto(self, buffer_out, buffer_in):
  92         return self.write_readinto(buffer_out, buffer_in)
  93
  94
  95 class UART(Lockable):
  96     class Parity(Enum):
  97         pass
  98
  99     Parity.ODD = Parity()
 100     Parity.EVEN = Parity()
 101
 102     # TODO investigate UART receiver_buffer_size as e.g. read_buf_len in https://github.com/micropython/micropython/blob/3eb0694b97c6a8f0e93b874549aac40d8b78b0e5/ports/stm32/uart.c
 103     def __init__(self,
 104                  tx,
 105                  rx,
 106                  baudrate=9600,
 107                  bits=8,
 108                  parity=None,
 109                  stop=1,
 110                  timeout=1000,
 111                  receiver_buffer_size=64,
 112                  flow=None):
 113         from machine import UART as _UART
 114         from microcontroller.pin import uartPorts
 115
 116         self.baudrate = baudrate
 117
 118         if flow is not None:  # default 0
 119             raise NotImplementedError(
 120                 "Parameter '{}' unsupported on {}".format(
 121                     "flow", agnostic.board))
 122
 123         # translate parity flag for Micropython
 124         if parity is UART.Parity.ODD:
 125             parity = 1
 126         elif parity is UART.Parity.EVEN:
 127             parity = 0
 128         elif parity is None:
 129             pass
 130         else:
 131             raise ValueError("Invalid parity")
 132
 133         # check tx and rx have hardware support
 134         for portId, portTx, portRx in uartPorts:  #
 135             if portTx == tx and portRx == rx:
 136                 self._uart = _UART(
 137                     portId,
 138                     baudrate,
 139                     bits=bits,
 140                     parity=parity,
 141                     stop=stop,
 142                     timeout=timeout,
 143                     read_buf_len=receiver_buffer_size
 144                 )
 145                 break
 146         else:
 147             raise NotImplementedError(
 148                 "No Hardware UART on (tx,rx)={}\nValid UART ports".format(
 149                     (tx, rx), uartPorts))
 150
 151     def deinit(self):
 152         self._uart = None
 153
 154     def read(self, nbytes=None):
 155         return self._uart.read(nbytes)
 156
 157     def readinto(self, buf, nbytes=None):
 158         return self._uart.readinto(buf, nbytes)
 159
 160     def readline(self):
 161         return self._uart.readline()
 162
 163     def write(self, buf):
 164         return self._uart.write(buf)