src/adafruit_blinka/microcontroller/nova/spi.py

   1 class SPI:
   2     PAYLOAD_MAX_LENGTH = 64
   3
   4     def __init__(self, clock):
   5         from adafruit_blinka.microcontroller.nova import Connection
   6         self._nova = Connection.getInstance()
   7         self._nova.setOperationMode(0, 'SPI')
   8         self._nova.setClockSPI(0, clock)
   9         self._nova.setModeSPI(0, 0)
  10         self._nova.setIOpinMode(0, 'DOUT')
  11         self._nova.setIOpinValue(0, 'HIGH')
  12         self._nova.beginSPI(0)
  13         # Cpol and Cpha set by mode
  14         # Mode  Cpol Cpha
  15         #  0     0    0
  16         #  1     0    1
  17         #  2     1    0
  18         #  3     1    1
  19
  20     def init(self, baudrate=100000, polarity=0, phase=0, bits=8,
  21                   firstbit=MSB, sck=None, mosi=None, miso=None):
  22         print("baudrate: " + baudrate)
  23         print("mode: " + (polarity<<1) | (phase))
  24         self._nova.setClockSPI(0, baudrate)
  25         self._nova.setModeSPI(0, (polarity<<1) | (phase))
  26
  27     @staticmethod
  28     def getSpiReceivedData(lineOutput):
  29         return (lineOutput.split('RXD ')[1])
  30
  31     @property
  32     def frequency(self):
  33         return self._nova.getClockSPI(0).split('CLK ')[1]
  34
  35     def write(self, buf, start=0, end=None):
  36         end = end if end else len(buf)
  37         chunks, rest = divmod(end - start, self.PAYLOAD_MAX_LENGTH)
  38         self._nova.setIOpinValue(0, 'LOW')
  39         for i in range(chunks):
  40             chunk_start = start + i * self.PAYLOAD_MAX_LENGTH
  41             chunk_end = chunk_start + self.PAYLOAD_MAX_LENGTH
  42             buffer_data = buf[chunk_start:chunk_end]
  43             self._nova.clearBuffer(0)
  44             self._nova.writeToBuffer(0, 0, buffer_data)
  45             self._nova.transferBufferSPI(0, chunk_end - chunk_start + 1)
  46         if rest:
  47             buffer_data = buf[-1*rest:]
  48             self._nova.clearBuffer(0)
  49             self._nova.writeToBuffer(0, 0, buffer_data)
  50             self._nova.transferBufferSPI(0, rest)
  51         self._nova.setIOpinValue(0, 'HIGH')
  52         print(self._nova.readBuffer(0, 4))
  53
  54     def readinto(self, buf, start=0, end=None, write_value=0):
  55         end = end if end else len(buf)
  56         self._nova.setIOpinValue(0, 'LOW')
  57         for i in range(start, end):
  58             buf[start+i] = int(self.getSpiReceivedData(self._nova.transferSPI(0, write_value)), 16)
  59         self._nova.setIOpinValue(0, 'HIGH')
  60
  61     def write_readinto(self, buffer_out, buffer_in,  out_start=0, out_end=None, in_start=0, in_end=None):
  62         out_end = out_end if out_end else len(buffer_out)
  63         in_end = in_end if in_end else len(buffer_in)
  64         readlen = in_end-in_start
  65         writelen = out_end-out_start
  66         if readlen > writelen:
  67             # resize out and pad with 0's
  68             tmp = bytearray(buffer_out)
  69             tmp.extend([0] * (readlen - len(buffer_out)))
  70             buffer_out = tmp
  71         i = 0
  72         self._nova.setIOpinValue(0, 'LOW')
  73         for data_out in buffer_out:
  74             data_in = int(self.getSpiReceivedData(self._nova.transferSPI(0, data_out)), 16)
  75             if i < readlen:
  76                 buffer_in[in_start+i] = data_in
  77             i += 1
  78         self._nova.setIOpinValue(0, 'HIGH')