When it gets a chance to run, it performs the virtual machine functions of interpreting the gecko codes, and services the debug commands pending on the EXI port if any are ready. The codehandler on the Wii side is inserted in some commonly called function like the function to wait for vertical blank. The code handler also has functionality to support debugging functions, such as setting breakpoints, viewing or writing memory, or pausing a program in progress. The code handler takes care of interpreting the cheat code virtual machine which can be used to play games with infinite lives, health or whatever hack a person might desire. The PC side sends bytes over to the Wii to control the installed code handler. This is not strictly necessary for the USB Gecko's main functionality. There is a 512K byte flashrom, the SST39VF040 which is accessable only on the Wii side through the Altera CPLD.The FIFOs are connected to an ALTERA CPLD (Complex Programmable Logic Device) EPM570T100C5N which converts the parallel data to the serial datastream needed for the Wii's EXI port.One sends data to the Wii (128 byte capacity), the other receives data from the Wii (256 byte capacity). The USB interface is provided by the FT245RL which converts USB to two 8 bit bidirectional FIFOs.

The pins are, in order from left to right (matching the bottom picture at right): The pins on the back side connect to the Altera CPLD's JTAG pins for programming. The pins on the front side are what connect to the Wii EXI port. Pin 3 is the EXI interrupt pin, which is unconnected for some unknown reason. The pins on the bottom connector are numbered from left to right 12 down to 1, even numbers being on the bottom row, odd numbers being on the top row. In theory one could open up the USB Gecko and run a trace from that pin to one of the many unused pins on the CPLD, reprogram the CPLD, and be able to trigger the EXI interrupt from the PC side. The EXI interrupt cannot be triggered from the PC because the pin on the Wii side is left unconnected. The USB Gecko is a two step converter to convert EXIserialusb. The USBGecko will appear as 0403:6001 in the lsusb output. Simply writing to and reading from this device file will send data across the USBGecko link.įailing that, userspace tools could use the libusb library and usb_bulk_write and usb_bulk_read functions.

The USB Gecko will usually be recognized as a USB to serial port converter and a device file of the form (Using the above D2XX API to transfer data is functionally equivalent) The device will also be recognised as a COM serial port if drivers have been installed, reading and writing to this port will transfer the data across the Gecko. Drivers and documentation for the FTDI chip used in the USB Gecko can be found on FTDI's website: Drivers and API downloads, API Documentation

Usb to gamecube memory card