Rainbow Electronics AT89C5132 - Manual (Page 68)

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AT8xC5132
4173A–8051–08/02
Universal Serial Bus
The AT8xC5132 implement a USB device controller supporting Full-speed data transfer.
In addition to the default control endpoint 0, it provides 3 other endpoints, which can be
configured in Control, Bulk, Interrupt or Isochronous types.
This allows to develop firmware conforming to most USB device classes, for example
the AT8xC5132 support:
• USB Mass Storage Class Control/Bulk/Interrupt (CBI) Transport, Revision 1.0 –
December 14, 1998
• USB Mass Storage Class Bulk-Only Transport, Revision 1.0 – September 31, 1999
• USB Device Firmware Upgrade Class, Revision 1.0 – May 13, 1999
USB Mass Storage Class CBI
Transport Within the CBI framework, the Control endpoint is used to transport command blocks as
well as to transport standard USB requests. One Bulk Out endpoint is used to transport
data from the host to the device. One Bulk In endpoint is used to transport data from the
device to the host. And one interrupt endpoint may also be used to signal command
completion (protocol 0) but it is optional and may not be used (protocol 1).
The following AT8xC5132 configuration adheres to that requirements:
• Endpoint 0: 32 Bytes, Control In-Out
• Endpoint 1: 64 Bytes, Bulk Out
• Endpoint 2: 64 Bytes, Bulk In
• Endpoint 3: 8 Bytes, Interrupt In
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. No interrupt
endpoint is needed.
The following AT8xC5132 configuration adheres to that requirements:
• Endpoint 0: 32 Bytes, Control In-Out
• Endpoint 1: 64 Bytes, Bulk Out
• Endpoint 2: 64 Bytes, Bulk In
• Endpoint 3: not used
USB Device Firmware
Upgrade (DFU) The USB Device Firmware Update (DFU) protocol can be used to upgrade the on-chip
Flash memory of the AT89C5132. This allows installing product enhancements and
patches to devices that are already in the field. Two different configurations and descrip-
tor sets are used to support DFU functions. The Run-Time configuration co-exist with
the usual functions of the device, which shall be USB Mass Storage for AT89C5132. 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 ser-
vices 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.