https://github.com/scruss/micropython-MCP3001

MicroPython library for the MCP3001 10-bit 1-channel SPI Analogue-Digital converter
https://github.com/scruss/micropython-MCP3001

adc mcp3001 microchip micropython

Last synced: about 19 hours ago
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MicroPython library for the MCP3001 10-bit 1-channel SPI Analogue-Digital converter

• Host: GitHub
• URL: https://github.com/scruss/micropython-MCP3001
• Owner: scruss
• License: mit
• Created: 2024-11-06T16:23:56.000Z (9 days ago)
• Default Branch: main
• Last Pushed: 2024-11-06T18:21:04.000Z (9 days ago)
• Last Synced: 2024-11-06T19:24:20.019Z (9 days ago)
• Topics: adc, mcp3001, microchip, micropython
• Language: Python
• Homepage: https://github.com/scruss/micropython-MCP3001
• Size: 140 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

• awesome-micropython - micropython-MCP3001 - MicroPython driver for the MCP3001 1-channel 10-bit ADC with SPI interface. (Libraries / IO)

README

        
# micropython-MCP3001

MicroPython library for the MCP3001 10-bit 1-channel SPI

Analogue-Digital converter

This library enables an MCP3001 ADC to be used with any MicroPython

implementation that supports SPI. Almost all MicroPython-capable

boards have adequate ADCs onboard, so you might only want to use this

library if:

* your board has no ADC (like the Wemos

  [W600-PICO](https://www.wemos.cc/en/latest/w600/w600_pico.html#w600-pico))

  or a very limited one (as on the ESP8266); or

  

* you wish to use an external reference voltage source such as an

  LM4040.

  

## Installation

Copy the `mcp3001.py` file to your MicroPython board's filesystem,

typically to the root or `/lib` folder.

## Usage

```python3

import mcp3001

# …

adc = mcp3001.MCP3001(spi, cs)

```

### Initialization

```

MCP3001(spi, cs [, ref_voltage])

```

* `spi` is an instance of a [Serial Peripheral Interface

  bus](https://docs.micropython.org/en/latest/library/machine.SPI.html)

  object, for example `spi = machine.SPI(0)`

  

* `cs` is an instance of an [I/O

  pin](https://docs.micropython.org/en/latest/library/machine.Pin.html)

  object, configured for output and ideally initially set high. An

  example might be `cs = machine.Pin(17, machine.Pin.OUT, value=1)`

  

* `ref_voltage` is an optional argument to manually set the

  reference voltage. If it is not specified as a float, the value of

  3.3 is assumed.

  

### Methods

* `read()` — returns an integer ADC reading from 0–1023.

* `read_u16()` — returns an integer ADC reading from 0—65535. This

  is provided for compatibility with MicroPython's

  [method of the same name](https://docs.micropython.org/en/latest/library/machine.ADC.html#machine.ADC.read_u16).

  

* `read_v()` — returns a floating-point ADC reading from

  0.0 – *reference voltage* volts.

  

* `reference_voltage()` — returns the ADC reference voltage as a

  floating-point value. Returns 3.3 if none was given during

  initialization.

## Example

An MCP3001 is used to read the value of a potentiometer into a

Raspberry Pi Pico. The brown wires in the diagram indicate analogue

ground, and have been kept separate from the black system ground

wires. If your board doesn't have a separate **AGND** connection, a

regular **GND** connection will do.

The default `SPI(0)` pins have been used on the Raspberry Pi Pico:

GP16 for RX, GP17 for CSn and GP18 for SCK. In the absence of an

external reference voltage, **3V3(OUT)** has been connected to

**VREF** on the MCP3001.



Code: [test_mcp3001.py](test_mcp3001.py)

## Device information

Datasheet: [MicroChip MCP3001 2.7V 10-Bit A/D Converter with SPI™

Serial

Interface](https://ww1.microchip.com/downloads/aemDocuments/documents/APID/ProductDocuments/DataSheets/21293C.pdf)

### Pinout

1. **VREF** — analogue reference voltage. Should not exceed

   **VDD**.

2. **IN+** — Positive analogue input. While **IN+** and **IN-** form a

   pseudo-differential pair, they can't float completely unrelated to

   system voltages. Please refer to the datasheet.

3. **IN-** — Negative analogue input. Typically connected to

   **VSS**, or analogue ground (**AGND**) if your

   micro-controller has it.

4. **VSS** — Ground.

5. **CS/SHDN** — SPI

   Chip Select (active low) and combined ADC shutdown line.

6. **DOUT** — SPI serial data out.

7. **CLK** — SPI serial data clock.

8. **VDD** — power supply, 2.7–5.5 V DC.

Note that the MCP3001, unlike other chips in the MCP300x range, has no

SPI **DIN** pin. Its entire operation is controlled by the

**CS/SHDN** pin, and

only the data out and clock lines are used.

## Credits

© Stewart Russell — scruss.com, 2024.

Based on Romilly Cocking's

[mcp3008.py](https://github.com/romilly/pico-code/blob/master/src/pico_code/pico/mcp3008/mcp3008.py)

library.