Technical Precisions About The Nusbio Device

What is Nusbio?

Nusbio is USB device that bring the following to a Windows machine and the Microsoft .NET Runtime:

Device

• Gpios

• 8GPIO pins
• 3 or 5 volts 
• Nusbio version based on the chip FT232RL can be changed between 3.3 and 5 volts (GPIO and VCC). In 2017 only the version based on the FT232RL will be sold.
• Nusbio version based on the chip FT231X only the VCC can be changed between 3.3 and 5 volts. The GPIO are always 3.3 volts.
• Modes: OUTPUT or INPUT PULL UP.
• Maximum current per GPIO pin default 4 mA .
  The Console application allows to switch from 4 to 16 mA.
  In 16 mA of current mode we noticed that the I2C protocol does not work.

 Powering devices connected to Nusbio

• The VCC output from Nusbio provides 5 or 3.3 volts and up to 500 mA of current as defined by the USB 2.0 standard.
• The VCC output can be used to power other devices connected to Nusbio.
• Some Nusbio version based on the FT231X have a fuse that will limit the consumption to 500 mA of current.
• The voltage can be changed depending on the version as follow:
• De-soldering the 5 volts connector and soldering the 3 volts connector.
• Or switch the jumper between 5 volts and 3 volts

• SPI Protocol

• Mode

• Clock MODE_CPOL0_CPHA0 supported and tested
• The other 3 modes have been implemented but not tested.

• Tested Devices

• MCP3008 - 8 DAC
• MAX7219 - 7-Segment Driver
• 25AA256 - 32k EEPROM
• 25AA1024 - 128k EEPROM
• MCP23S08 - 8 Gpio Expander 
• OLED drivers
• SD1306
• SH1106
• SPI Compatible Devices
• 74HC595 - Shift register
• APA102 RGB LED

• SPI Slave

• Number of devices on an SPI bus. Since Nusbio comes with 8 gpios, we can control 5 (8-3 (clock, miso, mosi)) SPI devices on the same bus.

• Transfert Speed

• When data in and data out communication is needed (MOSI and MISO) the maximum transfer rate is around 15 k byte/s with no optimization.
• With specific optimization for EEPROM downloading in batch of 128 pages of 64 bytes, the transfer rate can go up to 28 k byte/s.
• Generally speaking when only data out communication is needed (no MISO) the transfer rate can go up to 20 k byte/s by using the class GpioSequence rather than the class SPIEngine. The class GpioSequence offers a way to optimize the bit banging.
• Transfer speed vary depending on the SPI device and the Windows PC.
• Nusbio and the C# class SPIEngine can transfer in one USB operation multiple SPI buffer (Select + Data + UnSelect + Select + Data + UnSelect).
• Some SPI device like the OLED driver SH1106 or SSD1306, required on top of the Select pin (CS) another pin named D/C (Data or Command). Nusbio and the C# class SPIEngine can transfer in one USB operation multiple SPI buffer (Select + D/C + Data + UnSelect + Select + D/C + Data + UnSelect. (See our source code on GitHub).

• I2C Protocol

• Tested Devices:
• 24LC256 32k EEPROM
• MCP2308 - 8 Gpio Expander 
• MCP9808 - Temperature sensor
• MCP4725 - 12Bit DAC 
• HT16K33 - Matrix Driver 
• Adafruit I2C LED Matrix devices
• Transfer Speed 
• The tests were performed by downloading 32k from the I2C EEPROM 24LC256 . 
• Transfer speed around 7.5K byte/s. 
• Transfer speed vary depending on the device and the Windows PC.

• SPI and I2C Protocol Combined

  With Nusbio it is possible to control SPI and I2C devices from the same configuration. For example
  
  
  
  • GPIO 0,1,2 would be reserved for SPI BUS: CLOCK, MOSI and MISO
  • GPIO 3,4,5 would be used as SELECT for 3 SPI Devices
  • GPIO 6,7 would be used as SDA and SCK for the I2C bus, allow to control up to 127 devices
  
  

• UART

  Nusbio can also play the role of an UART (FTDI cable, FTDI Friend) to upload data into an micro-controller like an Adafruit Trinket or Diavolino.
  The .NET library MadeInTheUSB.Lib.dll does not support this mode. The Arduino IDE will support Nusbio to upload code into an micro-controller with no UART.
  

  Videos

  • Nusbio - Nusbio As a FTDI Cable Adapter - PART I 
  • Nusbio - Nusbio As a FTDI Cable Adapter - PART II 

•  Library/Assembly

  • The MadeInTheUSB.Nusbio.Lib .NET assembly give access to the Nusbio device to any .NET language.
  • The MadeInTheUSB.Nusbio.Components assembly contains classes for specific components including the one used in the Nusbio's extensions.
  • Github Source
  
  

• Internal EEPROM

  Nusbio can store up to 32 bytes of data into the Description field. Though the Description property is a .NET string, the EEPROM only support ASCII string.

• Unique Serial Number

  Each Nusbio device is initialized with a unique Serial Number. See property SerialNumber.

Chip

Nusbio is based on the FTDI FT231X chip (Datasheet) or the FT232RL.
In 2017 only the FT232RL chip is used.