Untested busio implementation

diff --git a/python/busio/__init__.py b/python/busio/__init__.py
new file mode 100644 (file)
index 0000000..39432fc
--- /dev/null
+++ b/python/busio/__init__.py
@@ -0,0 +1,89 @@
+import agnostic
+from mcp import Enum, Lockable
+
+class SPI(Lockable):
+    def __init__(self, clock, MOSI=None, MISO=None):
+        from microcontroller import spiPorts
+        for spiId, sck, mosi, miso in spiPorts:
+            if sck == clock.id and mosi == MOSI.id and miso == MISO.id:
+                self._spi = SPI(spiId)
+                self._pinIds = (sck, mosi, miso)
+                break
+        else:
+            raise NotImplementedError("No Hardware SPI on (clock, MOSI, MISO)={}\nValid SPI ports:{}".format((clock, MOSI, MISO), spiPorts))
+
+    def configure(self, baudrate=100000, polarity=0, phase=0, bits=8):
+        if self._locked:
+            from machine import Pin
+            from microcontroller import spiPorts
+            # TODO check if #init ignores MOSI=None rather than unsetting, to save _pinIds attribute
+            self._spi.init(baudrate=baudrate, polarity=polarity, phase=phase, bits = bits, firstbit = SPI.MSB, sck = Pin(self._pinIds[0]), mosi=Pin(self._pinIds[1]), miso=Pin(self._pinIds[2]))
+        else:
+            raise RuntimeError("First call try_lock()")
+
+    def deinit(self):
+        self._spi = None
+        self._pinIds = None
+
+    def write(self, buf):
+        return self._spi.write(buf)
+
+    def readinto(self, buf):
+        return self.readinto(buf)
+
+    def write_readinto(self, buffer_out, buffer_in)
+        return self.write_readinto(buffer_out, buffer_in)
+
+class UART(Lockable):
+
+    class Parity(Enum):
+        pass
+    Parity.ODD=Parity()
+    Parity.EVEN=Parity()
+
+    # TODO investigate UART receiver_buffer_size as e.g. read_buf_len in https://github.com/micropython/micropython/blob/3eb0694b97c6a8f0e93b874549aac40d8b78b0e5/ports/stm32/uart.c
+    def __init__(self, tx, rx, baudrate=9600, bits=8, parity=None, stop=1, timeout=None, receiver_buffer_size=None, flow=None):
+        from microcontroller import uartPorts
+        from machine import UART
+
+        self.baudrate = baudrate
+
+        if timeout is not None: # default 1000
+            raise NotImplementedError("Parameter '{}' unsupported on {}".format("timeout", agnostic.board))
+        if receiver_buffer_size is not None: # default 64
+            raise NotImplementedError("Parameter '{}' unsupported on {}".format("receiver_buffer_size", agnostic.board))
+        if flow is not None: # default 0
+            raise NotImplementedError("Parameter '{}' unsupported on {}".format("flow", agnostic.board))
+
+        # translate parity flag for Micropython
+        if parity is UART.Parity.ODD:
+            parity = 1
+        elif parity is UART.Parity.EVEN:
+            parity = 0
+        elif parity is None:
+            pass
+        else:
+            raise ValueError("Invalid parity")
+
+        # check tx and rx have hardware support
+        for portId, portTx, portRx in uartPorts:#
+            if portTx == tx.id and portRx == rx.id:
+                self._uart = UART(portId, baudrate, bits=bits, parity=parity, stop=stop, timeout=timeout)
+                break
+        else:
+            raise NotImplementedError("No Hardware UART on (tx,rx)={}\nValid UART ports".format((tx, rx), uartPorts))
+
+    def deinit(self):
+        self._uart = None
+
+    def read(self, nbytes=None):
+        return self._uart.read(nbytes)
+
+    def readinto(self, buf, nbytes=None):
+        return self._uart.readinto(buf, nbytes)
+
+    def readline(self):
+        return self._uart.readline()
+
+    def write(self, buf):
+        return self._uart.write(buf)