AT43USB370E-AC

Overview

The AT43USB370E-AC is a USB 2.0 compliant, dual-role, full-speed Host/Function processor designed for embedded point-to-point connectivity. It integrates an on-chip USB transceiver, Serial Interface Engine (SIE), and two internal microcontrollers: the USB Controller (USBC) and System Interface Controller (SIC). The device supports autonomous host operation without system processor intervention, managing enumeration, protocol, and bandwidth reclamation. It features a 32-bit generic system processor interface with DMA support, separate TX/RX buffers, and in-system firmware upgrade capability. Operating at 6 MHz with 1.8 V and 3.3 V supplies, it is housed in a 100-pin LQFP package.

Feature Summary

• Dual-role USB 2.0 Full-Speed Host/Function Processor with real-time switching capability
• Autonomous USB Host Operation including device enumeration and protocol management
• Integrated USB Firmware with ANSI C compliant API for device driver development
• 32-bit Generic System Processor Interface with DMA engine and 2 Kbytes FIFO

Applications

• Embedded devices requiring point-to-point USB connectivity
• Resource-constrained environments offloading USB processing from system processors
• Applications utilizing in-system firmware upgrades for USB controllers

Procurement Notes

Verify the E-AC suffix against official Microchip documentation to confirm specific environmental or packaging classifications. Ensure compatibility with the required 1.8 V and 3.3 V power supply rails during design validation. Confirm that the 100-pin LQFP footprint matches the target PCB layout specifications.

Selection Notes

Select this component when a dedicated USB controller is needed to offload timing-critical USB activities from the main system processor. It is suitable for designs requiring both host and function capabilities within a single chip. Ensure the external system processor supports the 32-bit memory-mapped interface and DMA signaling required for data transfer.

Part Context

The AT43USB370 is part of Atmel's (now Microchip Technology) USB processor family. It is distinct from general-purpose MCUs by focusing exclusively on USB protocol handling via integrated firmware. The device complements system processors by providing hardware-based USB transaction management and data buffering.

Replacement Considerations

Consult Microchip's official obsolescence notices and cross-reference tools for verified substitute part numbers. Do not assume functional equivalence with other USB controllers without verifying register compatibility and firmware requirements.

FAQ

How is the operating mode determined?

The mode of operation (host or function) is determined by writing corresponding values to specified registers and downloading the appropriate USBC and SIC firmware to the AT43USB370.

What is the clock source requirement?

The AT43USB370 requires an external 6-MHz crystal to provide a reference clock frequency for the on-chip PLL, which generates all internal clock sources.

Can the device operate without system processor intervention?

Yes, in host mode, the integrated USB firmware allows for autonomous operation, including device enumeration and transaction management, without system processor intervention.