Specifications

AT83SND2CMP3

7524D–MP3–07/07

Universal Serial Bus

The product implements a USB device controller supporting full speed data transfer. In

addition to the default control endpoint 0, it provides 2 other endpoints, which can be

configured in control, bulk, interrupt or isochronous modes:

• Endpoint 0: 32-Byte FIFO, default control endpoint

• Endpoint 1, 2: 64-Byte Ping-pong FIFO,

This allows the firmware to be developed conforming to most USB device classes, for

example:

• USB Mass Storage Class Bulk-only Transport, Revision 1.0 - September 31, 1999

• USB Human Interface Device Class, Version 1.1 - April 7, 1999

• USB Device Firmware Upgrade Class, Revision 1.0 - May 13, 1999

USB Mass Storage Class

Bulk-Only Transport

Within the Bulk-only framework, the Control endpoint is only used to transport class-

specific and standard USB requests for device set-up and configuration. One Bulk-out

endpoint is used to transport commands and data from the host to the device. One Bulk

in endpoint is used to transport status and data from the device to the host.

The following AT83SND2CMP3 configuration adheres to those requirements:

• Endpoint 0: 32 Bytes, Control In-Out

• Endpoint 1: 64 Bytes, Bulk-in

• Endpoint 2: 64 Bytes, Bulk-out

USB Device Firmware

Upgrade (DFU)

The USB Device Firmware Update (DFU) protocol can be used to upgrade the on-chip

Flash memory of the AT83SND2CMP3. This allows installing product enhancements

and patches to devices that are already in the field. 2 different configurations and

descriptor sets are used to support DFU functions. The Run-Time configuration co-exist

with the usual functions of the device, which is USB Mass Storage for AT83SND2CMP3.

It is used to initiate DFU from the normal operating mode. The DFU configuration is

used to perform the firmware update after device re-configuration and USB reset. It

excludes any other function. Only the default control pipe (endpoint 0) is used to support

DFU services in both configurations.

The only possible value for the MaxPacketSize in the DFU configuration is 32 Bytes,

which is the size of the FIFO implemented for endpoint 0.