The USB-ISS module is powered from a USB type-B connector. Alternatively, it can be powered from 3.3V source by removing the "power link" jumper. The module can supply up to 80mA at 5.0V for external circuitry from a standard 100mA USB port. Drivers are required for operation under Windows. When used on a Mac OS X or Linux based operating system, the USB-ISS will manifest as a virtual serial port (CDC device) in the system device tree. This means it will show up as COMX in Windows and in the device tree (/dev/tty....) in Mac OS X and Linux platforms.
Use the "power link" jumper to operate from 5V, or remove it for 3.3V
The USB-ISS can operate from 3.3V or 5V. With the LEDs on, it takes approximately 20mA. From a standard 100mA USB port, when operating at 5V, the USB-ISS module can supply up to 80mA to external devices. When the jumper is removed, a 3.3V regulator supplies the power. This regulator is capable of 50mA, so when running at 3.3V approximately 30mA is available to external devices. Do not apply your own voltage to this pin.
The Green LED is a power indicator and is on when the module is connected to a powered USB port. The Red LED will flash whenever there is a valid I2C or SPI command received.
Each I/O pin, 1 to 4, may be individually selected to be analog input or digital Input or digital output. Inputs will not accept voltage higher than the selected supply voltage, so when operating at 3.3V the inputs are not 5V tolerant. Analog inputs span from 0v to the supply votlage, and are connectedt to a 10-bit ADC.
SCL and SDA
These pins are the I2C bus connections. They should be connected directly to the SCL and SDA pins on your I2C device. The USB-ISS module is always a bus master, and is fitted with 4.7kΩ pull-up resistors. These resistors are automatically disconnected in other modes.
SDI, SCK, SDO and CE
SDI is the SPI input to the USB-ISS, connect it to SDO on your device.
SDO is the SPI output from the USB-ISS, connect it to SDI on your device.
SCK is the SPI clock output from the USB-ISS, connect it to SCK on your device.
CE is the active low chip enable signal, connect it to CE on your device.
These are logic level signals, not RS232. Do not connect this to an RS232 port without using a suitable RS232 logic level adapter.
The 0v Ground pin must be connected to the 0v (Ground) on your device.
See the technical documentation for the command interface.