src/adafruit_blinka/microcontroller/nova/spi.py

   1 """SPI Class for Binho Nova"""
   2 from adafruit_blinka.microcontroller.nova import Connection
   3
   4
   5 class SPI:
   6     """Custom SPI Class for Binho Nova"""
   7
   8     MSB = 0
   9     PAYLOAD_MAX_LENGTH = 64
  10
  11     def __init__(self, clock):
  12         self._nova = Connection.getInstance()
  13         self._nova.setNumericalBase(10)
  14         self._nova.setOperationMode(0, "SPI")
  15         self._nova.setClockSPI(0, clock)
  16         self._nova.setModeSPI(0, 0)
  17         self._nova.setIOpinMode(0, "DOUT")
  18         self._nova.setIOpinMode(1, "DOUT")
  19         self._nova.beginSPI(0)
  20
  21         # Cpol and Cpha set by mode
  22         # Mode  Cpol Cpha
  23         #  0     0    0
  24         #  1     0    1
  25         #  2     1    0
  26         #  3     1    1
  27
  28     # pylint: disable=too-many-arguments,unused-argument
  29     def init(
  30         self,
  31         baudrate=100000,
  32         polarity=0,
  33         phase=0,
  34         bits=8,
  35         firstbit=MSB,
  36         sck=None,
  37         mosi=None,
  38         miso=None,
  39     ):
  40         """Initialize the Port"""
  41         # print("baudrate: " + str(baudrate))
  42         # print("mode: " + str((polarity<<1) | (phase)))
  43         self._nova.setClockSPI(0, baudrate)
  44         self._nova.setModeSPI(0, (polarity << 1) | (phase))
  45
  46     # pylint: enable=too-many-arguments,unused-argument
  47
  48     @staticmethod
  49     def get_received_data(lineOutput):
  50         """Return any received data"""
  51         return lineOutput.split("RXD ")[1]
  52
  53     @property
  54     def frequency(self):
  55         """Return the current frequency"""
  56         return self._nova.getClockSPI(0).split("CLK ")[1]
  57
  58     def write(self, buf, start=0, end=None):
  59         """Write data from the buffer to SPI"""
  60         end = end if end else len(buf)
  61         chunks, rest = divmod(end - start, self.PAYLOAD_MAX_LENGTH)
  62         for i in range(chunks):
  63             chunk_start = start + i * self.PAYLOAD_MAX_LENGTH
  64             chunk_end = chunk_start + self.PAYLOAD_MAX_LENGTH
  65             buffer_data = buf[chunk_start:chunk_end]
  66             self._nova.clearBuffer(0)
  67             self._nova.writeToBuffer(0, 0, buffer_data)
  68             self._nova.transferBufferSPI(0, chunk_end - chunk_start + 1)
  69         if rest:
  70             buffer_data = buf[-1 * rest :]
  71             self._nova.clearBuffer(0)
  72             self._nova.writeToBuffer(0, 0, buffer_data)
  73             self._nova.transferBufferSPI(0, rest)
  74
  75     def readinto(self, buf, start=0, end=None, write_value=0):
  76         """Read data from SPI and into the buffer"""
  77         end = end if end else len(buf)
  78         for i in range(start, end):
  79             buf[start + i] = int(
  80                 self.get_received_data(self._nova.transferSPI(0, write_value))
  81             )
  82
  83     # pylint: disable=too-many-arguments
  84     def write_readinto(
  85         self, buffer_out, buffer_in, out_start=0, out_end=None, in_start=0, in_end=None
  86     ):
  87         """Perform a half-duplex write from buffer_out and then
  88         read data into buffer_in
  89         """
  90         out_end = out_end if out_end else len(buffer_out)
  91         in_end = in_end if in_end else len(buffer_in)
  92         readlen = in_end - in_start
  93         writelen = out_end - out_start
  94         if readlen > writelen:
  95             # resize out and pad with 0's
  96             tmp = bytearray(buffer_out)
  97             tmp.extend([0] * (readlen - len(buffer_out)))
  98             buffer_out = tmp
  99         i = 0
 100         for data_out in buffer_out:
 101             data_in = int(self.get_received_data(self._nova.transferSPI(0, data_out)))
 102             if i < readlen:
 103                 buffer_in[in_start + i] = data_in
 104             i += 1
 105
 106     # pylint: enable=too-many-arguments