src/adafruit_blinka/microcontroller/rp2040/spi.py

   1 # SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries
   2 #
   3 # SPDX-License-Identifier: MIT
   4 """SPI Class for RP2040"""
   5 from machine import SPI as _SPI
   6 from machine import Pin
   7 from microcontroller.pin import spiPorts
   8
   9
  10 # pylint: disable=protected-access, no-self-use
  11 class SPI:
  12     """Custom SPI Class for RP2040"""
  13
  14     MSB = _SPI.MSB
  15
  16     def __init__(self, clock, MOSI=None, MISO=None, *, baudrate=1000000):
  17         self._frequency = baudrate
  18         for portId, portSck, portMosi, portMiso in spiPorts:
  19             if (
  20                 (clock == portSck)
  21                 and MOSI in (portMosi, None)  # Clock is required!
  22                 and MISO in (portMiso, None)  # But can do with just output
  23             ):  # Or just input
  24                 mosiPin = Pin(portMosi.id) if MOSI else None
  25                 misoPin = Pin(portMiso.id) if MISO else None
  26                 self._spi = _SPI(
  27                     portId,
  28                     sck=Pin(portSck.id),
  29                     mosi=mosiPin,
  30                     miso=misoPin,
  31                     baudrate=baudrate,
  32                 )
  33                 break
  34         else:
  35             raise ValueError(
  36                 "No Hardware SPI on (SCLK, MOSI, MISO)={}\nValid SPI ports:{}".format(
  37                     (clock, MOSI, MISO), spiPorts
  38                 )
  39             )
  40
  41     # pylint: disable=too-many-arguments,unused-argument
  42     def init(
  43         self,
  44         baudrate=1000000,
  45         polarity=0,
  46         phase=0,
  47         bits=8,
  48         firstbit=_SPI.MSB,
  49         sck=None,
  50         mosi=None,
  51         miso=None,
  52     ):
  53         """Initialize the Port"""
  54         self._frequency = baudrate
  55         self._spi.init(
  56             baudrate=baudrate,
  57             polarity=polarity,
  58             phase=phase,
  59             bits=bits,
  60             firstbit=firstbit,
  61         )
  62
  63     # pylint: enable=too-many-arguments
  64
  65     @property
  66     def frequency(self):
  67         """Return the current frequency"""
  68         return self._frequency
  69
  70     def write(self, buf, start=0, end=None):
  71         """Write data from the buffer to SPI"""
  72         self._spi.write(buf)
  73
  74     def readinto(self, buf, start=0, end=None, write_value=0):
  75         """Read data from SPI and into the buffer"""
  76         self._spi.readinto(buf)
  77
  78     # pylint: disable=too-many-arguments
  79     def write_readinto(
  80         self, buffer_out, buffer_in, out_start=0, out_end=None, in_start=0, in_end=None
  81     ):
  82         """Perform a half-duplex write from buffer_out and then
  83         read data into buffer_in
  84         """
  85         self._spi.write_readinto(
  86             buffer_out,
  87             buffer_in,
  88             out_start=out_start,
  89             out_end=out_end,
  90             in_start=in_start,
  91             in_end=in_end,
  92         )
  93
  94     # pylint: enable=too-many-arguments