p1 of 9
26-Aug-10
USB-SPI
HW144-8
www.hexwax.com
USB-I2CTM
Driver-free USB to synchronous serial I2C slave interface
Summary
USB-I2C is a single chip USB to synchronous serial I2C
slave interface. It greatly simplifies the connection of
personal computer to a microcontroller capable of
communicating in I2C master mode. In addition to the
standard 2 I2C control lines, 11 additional Virtual I/O
lines have custom-defined functionality.
USB-I2C uses the Human Interface Device (HID) USB
profile. It does not require USB driver installation, and
so is compatible with present and future Windows, Linux
and Mac operating systems.
USB-I2C is firmware for the PIC18LF2455 and
PIC18F14K50 microcontrollers. It requires only a few
discrete components and is available 28-pin DIL and 20-
pin SSOP packages.
For I2C master applications (to control I2C slave
devices), our expandIO-USB product is more suitable.
Features
Suitable for connection to I2C master devices
Single chip solution
True HID plug and play - No drivers required
USB 2.0 compatible
Achievable data transfer rates up to 600K baud
Max I2C clock rate 1MHz
32-bit serial number
128-byte FIFO receive buffer
128-byte FIFO transmit buffer
Operating voltage 1.8V – 5V
11 auxiliary I/O pins, configurable as digital I/O,
10-bit A-to-D, USB status
VID, PID, product descriptor and I/O configuration
may be specified at program time or at runtime
PIC18F14K50-based DIL, SSOP packages
PIC18LF2455-based DIL, SIOC packages
Mechanical
Specifications
Applications
USB I2C slave for connection to I2C host devices
USB data transfer for consumer products
USB industrial control
Firmware Factory USB Product Family
USB-232 asynchronous serial interface
TEAleaf-USB security and authentication dongle
expandIO-USB I/O expander
USB-I2C synchronous serial interface
USB-TakeOff managed power take-off, wakeup
and charge controller
USB-DAQ data logger
USB-FileSys USB embedded file system
Table 1. Electrical Specifications
Operating voltage (20 pin / 28 pin)
1.8V/2.7V–5.5V
Typical/max supply current, Vdd = 5.0
10mA / 21mA
Operating Temperature
-40°C to +85°C
Refer to base microcontroller data sheet for further information
Firmware Factory Ltd
2 Marshall St, 3
rd Floor
London W1F 9BB, UK
sales@firmwarefactory.com
support@firmwarefactory.com
USB
Status
Outputs
128-byte Rx buffer
USB
Engine
128-byte Tx buffer
I2C
Engine
Control
Inputs
128-byte Tx buffer
Auxiliary I/O
Serial
Data