Dedicated circuit and method for enumerating and operating a peripheral device on a universal serial bus

A device controller for use in a peripheral electronic device and configured to communicate with a host computer comprising:

• a central processing unit (CPU) configured to communicate with a host computer via a Universal Serial Bus (USB);
• a device memory for storing data;
• an interface that enables communication between the device controller and the USB;
• and
• a second controller responsive to the host computer sending a set-up signal for controlling enumeration of the peripheral device by communicating with the interface to exchange data with the host computer, the second controller further being responsive to a control signal from the CPU controlling the device memory to store data received by the host computer and for retrieving data to be sent to the host, and the second controller further being responsive to the CPU for relinquishing control of the peripheral device to the CPU.

A computer system comprising:

• a host computer configured to process data;
• a Universal Serial Bus (USB) communicating with the host computer;
• and
• a peripheral device communicating with the host computer via the USB for exchanging data with the host computer, the peripheral device including:
• a central processing unit (CPU) for managing communications between the peripheral device and the host computer;
• an interface for communication between the peripheral device and the USB;
• a device memory for storing data;
• and
• a second controller responsive to the host computer sending a set-up signal for controlling enumeration of the peripheral device by communicating with the interface to exchange data with the host computer, the second controller further being responsive to a control signal from the CPU controlling the device memory to store data received by the host computer and for retrieving data to be sent to the host computer, and the second controller further being responsive to the CPU for relinquishing control of the peripheral device to the CPU.

A method of controlling data transfers between a peripheral device and a host computer via a Universal Serial Bus (USB), the peripheral device having a central processing unit (CPU) for managing communications between the peripheral device and the host computer, a USB interface interfacing the CPU and a controller with the USB, and a device memory connected to the CPU and to the controller for storing data, the method comprising:

• receiving a set-up signal from the host computer at the controller;
• sending an acknowledgment signal from the controller to the host computer to acknowledge receipt of the set-up signal;
• sending peripheral device configuration data from the host computer to the controller in response to the acknowledgment signal, the configuration data defining parameters for communicating with the peripheral device;
• storing the configuration data in the device memory using the controller;
• and
• sending a signal from the controller to the CPU to cause the CPU to assume control of the peripheral device from the controller.