MCP2221

Full featured library MCP2221 (A) via USB HID.

Standard Adafruit link.

Features

Support full range of command and functionality, including:

• Password Protected

  • Access Password setting
  • new password Flash writes
  • Alter Security settings
  • no guard against humans

• Status

  • Reset
  • Clear Interrupt
  • I²C Diagnostics
  • ADC output

• General Purpose

  • Digital In / Out (Gpio)
  • ADC 3x
  • DAC
  • Clock
  • Interrupt on Change (with variable edge detection)
  • USB Host Suspend and Configuration state

• I²C

  • standard direct methods
  • addition I2CBus abstraction support

• USB

  • USB Descriptor support
  • vendor / product Id
  • requested mA
  • etc

Example

import { MCP2221A } from '@johntalton/mcp2221'

const hidDevice = /* likely navigator.hid.getDevices() ... etc */
const source = new HIDStreamSource(hidDevice)
const chip = MCP2221.from(source)

const { adc } = await chip.common.status()
const { ch0, ch1, ch2 } = adc

ReadableStream / WritableStream

WebHID (and other HID implementation) can be abstracted in several way, an attempt is made here to normalized over a Stream API that supports BYOB (bring you own buffer) and Byte specific stream.

As such, a HIDStreamSource is used to normalize the WebHID (EventTarget) API into a stream.

A simplified stream reader is used which ignore (assumes zero) the report Id, which is correct in this case.