commit 363eaa46ef5ac7567d03e4175b07b39d7e8eaf3e
Author: Correl <correl@gmail.com>
Date:   Wed May 17 18:10:49 2023 -0400

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..e38da20
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+settings.json
diff --git a/main.py b/main.py
new file mode 100644
index 0000000..bef42ec
--- /dev/null
+++ b/main.py
@@ -0,0 +1,29 @@
+from machine import Pin, SPI, SoftI2C
+import framebuf
+import ssd1306
+import mcp4
+
+
+i2c = SoftI2C(sda=Pin(2), scl=Pin(16))
+oled_width = 128
+oled_height = 32
+oled = ssd1306.SSD1306_I2C(oled_width, oled_height, i2c)
+buf = bytearray((oled_height // 8) * oled_width)
+fbuf = framebuf.FrameBuffer1(buf, oled_width, oled_height)
+
+
+spi = SPI(1)
+cs = Pin(15, mode=Pin.OUT, value=1)
+pot = mcp4.MCP4(spi, cs)
+
+
+def update():
+    PW0 = pot.read(0)
+    PW1 = pot.read(1)
+    oled.fill(0)
+    oled.text(f"PW0: {PW0}", 0, 0)
+    oled.text(f"PW1: {PW1}", 0, 10)
+    oled.show()
+
+
+update()
diff --git a/mcp4.py b/mcp4.py
new file mode 100644
index 0000000..521918d
--- /dev/null
+++ b/mcp4.py
@@ -0,0 +1,164 @@
+"""MicroPython MCP413X/415X/423X/425X SPI driver
+
+Driver for the 7/8-Bit Single/Dual SPI Digital POT with Volatile Memory from
+Microchip. (https://ww1.microchip.com/downloads/en/DeviceDoc/22060b.pdf)
+
+Copyright 2023 Correl Roush
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the “Software”), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+"""
+
+from machine import Pin, SPI
+
+
+class NetworkControl:
+    def __init__(self, hw=True, a=True, w=True, b=True) -> None:
+        self.forced_hardware_shutdown = hw
+        self.terminal_a_connected = a
+        self.wiper_connected = w
+        self.terminal_b_connected = b
+
+    @staticmethod
+    def from_bin(data: int) -> "NetworkControl":
+        return NetworkControl(
+            hw=bool(data & 0b1000),
+            a=bool(data & 0b0100),
+            w=bool(data & 0b0010),
+            b=bool(data & 0b0001),
+        )
+
+    def __repr__(self):
+        return "<Network HW={hw} A={a} W={w} B={b}".format(
+            hw=self.forced_hardware_shutdown,
+            a=self.terminal_a_connected,
+            w=self.wiper_connected,
+            b=self.terminal_b_connected,
+        )
+
+
+class TerminalControl:
+    def __init__(self, resistor_0: NetworkControl, resistor_1: NetworkControl) -> None:
+        self.resistor_0 = resistor_0
+        self.resistor_1 = resistor_1
+
+    @staticmethod
+    def from_bin(data: int) -> "TerminalControl":
+        return TerminalControl(
+            resistor_0=NetworkControl.from_bin(data),
+            resistor_1=NetworkControl.from_bin(data >> 4),
+        )
+
+    def __repr__(self):
+        return "<Terminals 0:{r0} 1:{r1}>".format(
+            r0=self.resistor_0,
+            r1=self.resistor_1,
+        )
+
+
+class MCP4:
+    """MicroPython MCP413X/415X/423X/425X SPI driver"""
+
+    ADDRESS_WIPER_0 = 0x00
+    ADDRESS_WIPER_1 = 0x01
+    ADDRESS_TCON = 0x04
+    ADDRESS_STATUS = 0x05
+
+    CMD_WRITE = 0b00
+    CMD_INCREMENT = 0b01
+    CMD_DECREMENT = 0b10
+    CMD_READ = 0b11
+
+    def __init__(self, spi: SPI, cs: Pin) -> None:
+        self.spi = spi
+        self.cs = cs
+
+    def _bytes(self, address: int, command: int, data: int = 0x0) -> bytearray:
+        """Translate an address, command, and data into bytes to send.
+
+        - Address is a 4-bit memory address.
+        - Command is a 2-bit command code.
+        - Data is 2 bits for increment and decrement operations (ignored), and
+          10 bits for read and write operations.
+
+        """
+        command_byte = address << 4 & 0b11110000 | command << 2 & 0b00001100
+        if command in (0b00, 0b11):
+            # Include data byte for 10 total bits of data
+            return bytearray([command_byte | (0b11 & data >> 8), data & 0xFF])
+        return bytearray([command_byte])
+
+    def _write(self, data: bytearray) -> bytearray:
+        """Write data to the SPI interface, returning its output."""
+        output = bytearray(len(data))
+        self.spi.write_readinto(data, output)
+        return output
+
+    def do(self, address: int, command: int, data: int = 0x0) -> int:
+        """Execute a command on the MCP4, returning its integer result."""
+        self.cs(0)
+        output = self._write(self._bytes(address, command, data))
+        self.cs(1)
+
+        OK = 0b11111110
+        if OK != output[0] & OK:
+            self.cs(0)
+            raise ValueError("Invalid command")
+        result = output[0] & 0b01
+        if len(output) > 1:
+            result <<= 8
+            result |= output[1]
+        return result
+
+    def increment(self, wiper: int = 0) -> int:
+        """Increment a wiper."""
+        return self.do(
+            address=self.ADDRESS_WIPER_1 if wiper == 1 else self.ADDRESS_WIPER_0,
+            command=self.CMD_INCREMENT,
+        )
+
+    def decrement(self, wiper: int = 0) -> int:
+        """Decrement a wiper."""
+        return self.do(
+            address=self.ADDRESS_WIPER_1 if wiper == 1 else self.ADDRESS_WIPER_0,
+            command=self.CMD_DECREMENT,
+        )
+
+    def read(self, wiper: int = 0) -> int:
+        """Read the current value of a wiper."""
+        return self.do(
+            address=self.ADDRESS_WIPER_1 if wiper == 1 else self.ADDRESS_WIPER_0,
+            command=self.CMD_READ,
+        )
+
+    def write(self, wiper: int = 0, data: int = 0x00) -> int:
+        """Set a value for a wiper."""
+        return self.do(
+            address=self.ADDRESS_WIPER_1 if wiper == 1 else self.ADDRESS_WIPER_0,
+            command=self.CMD_WRITE,
+            data=data,
+        )
+
+    def is_shutdown(self) -> bool:
+        status = self.do(address=self.ADDRESS_STATUS, command=self.CMD_READ)
+        return status & 0b10 == 0b10
+
+    @property
+    def control(self) -> TerminalControl:
+        data = self.do(address=self.ADDRESS_TCON, command=self.CMD_READ)
+        return TerminalControl.from_bin(data)
diff --git a/ssd1306.py b/ssd1306.py
new file mode 100644
index 0000000..39ec081
--- /dev/null
+++ b/ssd1306.py
@@ -0,0 +1,167 @@
+#MicroPython SSD1306 OLED driver, I2C and SPI interfaces created by Adafruit
+
+import time
+import framebuf
+
+# register definitions
+SET_CONTRAST        = const(0x81)
+SET_ENTIRE_ON       = const(0xa4)
+SET_NORM_INV        = const(0xa6)
+SET_DISP            = const(0xae)
+SET_MEM_ADDR        = const(0x20)
+SET_COL_ADDR        = const(0x21)
+SET_PAGE_ADDR       = const(0x22)
+SET_DISP_START_LINE = const(0x40)
+SET_SEG_REMAP       = const(0xa0)
+SET_MUX_RATIO       = const(0xa8)
+SET_COM_OUT_DIR     = const(0xc0)
+SET_DISP_OFFSET     = const(0xd3)
+SET_COM_PIN_CFG     = const(0xda)
+SET_DISP_CLK_DIV    = const(0xd5)
+SET_PRECHARGE       = const(0xd9)
+SET_VCOM_DESEL      = const(0xdb)
+SET_CHARGE_PUMP     = const(0x8d)
+
+
+class SSD1306:
+    def __init__(self, width, height, external_vcc):
+        self.width = width
+        self.height = height
+        self.external_vcc = external_vcc
+        self.pages = self.height // 8
+        # Note the subclass must initialize self.framebuf to a framebuffer.
+        # This is necessary because the underlying data buffer is different
+        # between I2C and SPI implementations (I2C needs an extra byte).
+        self.poweron()
+        self.init_display()
+
+    def init_display(self):
+        for cmd in (
+            SET_DISP | 0x00, # off
+            # address setting
+            SET_MEM_ADDR, 0x00, # horizontal
+            # resolution and layout
+            SET_DISP_START_LINE | 0x00,
+            SET_SEG_REMAP | 0x01, # column addr 127 mapped to SEG0
+            SET_MUX_RATIO, self.height - 1,
+            SET_COM_OUT_DIR | 0x08, # scan from COM[N] to COM0
+            SET_DISP_OFFSET, 0x00,
+            SET_COM_PIN_CFG, 0x02 if self.height == 32 else 0x12,
+            # timing and driving scheme
+            SET_DISP_CLK_DIV, 0x80,
+            SET_PRECHARGE, 0x22 if self.external_vcc else 0xf1,
+            SET_VCOM_DESEL, 0x30, # 0.83*Vcc
+            # display
+            SET_CONTRAST, 0xff, # maximum
+            SET_ENTIRE_ON, # output follows RAM contents
+            SET_NORM_INV, # not inverted
+            # charge pump
+            SET_CHARGE_PUMP, 0x10 if self.external_vcc else 0x14,
+            SET_DISP | 0x01): # on
+            self.write_cmd(cmd)
+        self.fill(0)
+        self.show()
+
+    def poweroff(self):
+        self.write_cmd(SET_DISP | 0x00)
+
+    def contrast(self, contrast):
+        self.write_cmd(SET_CONTRAST)
+        self.write_cmd(contrast)
+
+    def invert(self, invert):
+        self.write_cmd(SET_NORM_INV | (invert & 1))
+
+    def show(self):
+        x0 = 0
+        x1 = self.width - 1
+        if self.width == 64:
+            # displays with width of 64 pixels are shifted by 32
+            x0 += 32
+            x1 += 32
+        self.write_cmd(SET_COL_ADDR)
+        self.write_cmd(x0)
+        self.write_cmd(x1)
+        self.write_cmd(SET_PAGE_ADDR)
+        self.write_cmd(0)
+        self.write_cmd(self.pages - 1)
+        self.write_framebuf()
+
+    def fill(self, col):
+        self.framebuf.fill(col)
+
+    def pixel(self, x, y, col):
+        self.framebuf.pixel(x, y, col)
+
+    def scroll(self, dx, dy):
+        self.framebuf.scroll(dx, dy)
+
+    def text(self, string, x, y, col=1):
+        self.framebuf.text(string, x, y, col)
+
+
+class SSD1306_I2C(SSD1306):
+    def __init__(self, width, height, i2c, addr=0x3c, external_vcc=False):
+        self.i2c = i2c
+        self.addr = addr
+        self.temp = bytearray(2)
+        # Add an extra byte to the data buffer to hold an I2C data/command byte
+        # to use hardware-compatible I2C transactions.  A memoryview of the
+        # buffer is used to mask this byte from the framebuffer operations
+        # (without a major memory hit as memoryview doesn't copy to a separate
+        # buffer).
+        self.buffer = bytearray(((height // 8) * width) + 1)
+        self.buffer[0] = 0x40  # Set first byte of data buffer to Co=0, D/C=1
+        self.framebuf = framebuf.FrameBuffer1(memoryview(self.buffer)[1:], width, height)
+        super().__init__(width, height, external_vcc)
+
+    def write_cmd(self, cmd):
+        self.temp[0] = 0x80 # Co=1, D/C#=0
+        self.temp[1] = cmd
+        self.i2c.writeto(self.addr, self.temp)
+
+    def write_framebuf(self):
+        # Blast out the frame buffer using a single I2C transaction to support
+        # hardware I2C interfaces.
+        self.i2c.writeto(self.addr, self.buffer)
+
+    def poweron(self):
+        pass
+
+
+class SSD1306_SPI(SSD1306):
+    def __init__(self, width, height, spi, dc, res, cs, external_vcc=False):
+        self.rate = 10 * 1024 * 1024
+        dc.init(dc.OUT, value=0)
+        res.init(res.OUT, value=0)
+        cs.init(cs.OUT, value=1)
+        self.spi = spi
+        self.dc = dc
+        self.res = res
+        self.cs = cs
+        self.buffer = bytearray((height // 8) * width)
+        self.framebuf = framebuf.FrameBuffer1(self.buffer, width, height)
+        super().__init__(width, height, external_vcc)
+
+    def write_cmd(self, cmd):
+        self.spi.init(baudrate=self.rate, polarity=0, phase=0)
+        self.cs.high()
+        self.dc.low()
+        self.cs.low()
+        self.spi.write(bytearray([cmd]))
+        self.cs.high()
+
+    def write_framebuf(self):
+        self.spi.init(baudrate=self.rate, polarity=0, phase=0)
+        self.cs.high()
+        self.dc.high()
+        self.cs.low()
+        self.spi.write(self.buffer)
+        self.cs.high()
+
+    def poweron(self):
+        self.res.high()
+        time.sleep_ms(1)
+        self.res.low()
+        time.sleep_ms(10)
+        self.res.high()
\ No newline at end of file