AT43USB380 Datasheet, PDF (1/8 Pages) ATMEL Corporation – On-The-Go Upgrade of the AT43USB370 USB 2.0 Full-Speed Host/Function Processor

Description
The AT43USB380 is a straightforward upgrade of the AT43USB370 Host/Function
Processor to support the USB 2.0 On-The-Go (OTG) specification. It can operate
either as a single-chip Host/Function Processor or if used in conjunction with an exter-
nal Atmel Charge Pump, as a full OTG solution.
The AT43USB380 is functionally equivalent to the AT43USB370 as a Host/Function
Processor and can be used in place of the AT43USB370 in the existing AT43USB370
design with minor hardware modifications. The pinout differences between the
AT43USB370 and the AT43USB380 are due to the inclusion of the on-chip OTG inter-
face in the AT43USB380.
To support OTG functionality, an external Charge Pump has to be connected to the
OTG interface of the AT43USB380, as shown in Figure 1 on page 7. The external
Charge Pump serves in the following two capacities:
1. As a power source to the downstream USB devices.
2. As a signaling interface during the OTG session negotiation upon connection.
From the hardware standpoint, the AT43USB380 is equivalent to the AT43USB370
with the following exceptions:
• On-chip OTG Interface. This hardware block is added to the AT43USB380 to
support the OTG functionality. Signals in the OTG interface include ID,
DISCHARGE, PUMP, CONTROL, EN, SESS_VLD, SESS_END, SESS_HIGH
and SESS_LOW. This interface is used during an OTG session to determine the
roles of the AT43USB380 and the connected OTG-enabled USB device either as
a host or a function.
• 8/16/32 Bit Generic Host Processor Interface. The AT43USB380 has a variable
width, generic host processor interface whereas the AT43USB370 supports only
32-bit host interface. The width of the host interface on the AT43USB380 is
determined by firmware configuration.
• Simplified System Interface. The GPIOs required in AT43USB370 for
handshaking are no longer required in AT43USB380. The system processor can
write directly to the AT43USB380 registers thus eliminates the need for PROG,
SEL, READY, DONE, MORE, INTR_IN signals. The WAIT_N signal is not needed
either. It is only there for precaution for SYS_CLK synchronization.
• Up to 16 GPIO Pins. GPIO pins are multiplexed with the host processor interface.
When the interface to the host processor is 8 or 16 bits, up to 16 of the unused
pins in the host processor interface can be used as GPIO pins. High level APIs
are provided to access these GPIO pins.
From the standpoint of the firmware development environment, the AT43USB380
shares the same high level APIs and low level firmware libraries with the
AT43USB370. Additions to the AT43USB380 firmware suite include:
• High level APIs specific to the OTG support. The number of additional APIs is
less than 10.
• Low level OTG firmware embedded in the AT43USB380 hardware that support
Host Negotiation Protocol (HNP) and Session Request Protocol (SRP).
The AT43USB380 share the same debugging tools with the AT43USB370 as well.
During development, the AT43USB380 should be treated as a black box in terms of
On-The-Go
Upgrade of the
AT43USB370
USB 2.0
Full-Speed
Host/Function
Processor
AT43USB380
Upgrade Map
Summary
3420AS–USB–03/04
Note: This is a summary document. A complete document
is not available at this time. For more information, please
contact your local Atmel sales office.