Interface Modules

Hardware

USB to I2C Slave

• "CJMCU-200" with FT200XD chipset
• Not very useful

USB to I2C Master

• "CJMCU-232H" with FTDI chipset FT232HQ (also including UART, SPI and GPIO)
• Datasheet
• Application Note
• Appear as /dev/ttyUSB0

Software:

• Linux: python3-pyftdi

/etc/udev/rules.d/11-ftdi.rules:

# FT232AM/FT232BM/FT232R
SUBSYSTEM=="usb", ATTR{idVendor}=="0403", ATTR{idProduct}=="6001", MODE="0664"
# FT2232C/FT2232D/FT2232H
SUBSYSTEM=="usb", ATTR{idVendor}=="0403", ATTR{idProduct}=="6010", MODE="0664"
# FT4232/FT4232H
SUBSYSTEM=="usb", ATTR{idVendor}=="0403", ATTR{idProduct}=="6011", MODE="0664"
# FT232H
SUBSYSTEM=="usb", ATTR{idVendor}=="0403", ATTR{idProduct}=="6014", MODE="0664"
# FT230X/FT231X/FT234X
SUBSYSTEM=="usb", ATTR{idVendor}=="0403", ATTR{idProduct}=="6015", MODE="0664"

python3:

>>> from pyftdi.ftdi import Ftdi
>>> Ftdi.show_devices()
Available interfaces:
 ftdi://ftdi:232h:2:b/1   (Single RS232-HS

Show device URLs:

ftdi_urls.py

Show I2C devices on bus:

i2cscan.py ftdi://ftdi:232h:2:b/1

BME820 I2C Temp/Humidity Sensor

• Schematic
• Default address: (Jumper can be moved to switch 0x77 / 0x76)

TinyRTC

• Default address:

Linux Interface

Packages: i2ctools, python-i2c

Detect buses:

 i2cdetect -l

BME820 I2C Temp/Humidity Sensor

• Schematic
• Jumper can be moved to switch address from 0x77 to 0x76

Linux Interface

Packages: i2ctools, python3-i2c-tools

Detect buses:

 i2cdetect -l

Board "CJMCU-232H" using the FTDI FT232H device. Similar to this.

• Datasheet
• Application Note
• Appear as /dev/ttyUSB0

USB interface to:

• UART mode (default operation, at 9600 8N1)
• MPSSE mode
  • SPI
  • I2C Master

• FTDI Drivers and libraries
  • D2XX drivers
  • I2C library built on D2XX
  • SPI library built on D2XX

• Open Source Drivers and libraries
  • libFTDI
  • libmpsse library for SPI and I2C built on libFTDI
  • ADAFruit Python interface for SPI, I2C and GPIO built on libFTDI
    • AdaFruit library setup

Pinouts:

Pin	UART Function	SPI	I2C	GPIO
C0
C1
C2
C3
C4
C5
C6
C7
C8
C9
D0	TX
D1	RX
D2	/RTS
D3	/CTS
D4	/DTR
D5	/DSR
D6	/DCD
D7	/RI