Maxim device makes adding USB to any microprocessor easy

Maxim Integrated Products unveiled its MAX3420E, a 12Mbps USB peripheral controller with an SPI interface. This device integrates all the necessary digital logic and analog circuitry to implement a full-speed USB peripheral compliant to the USB specification 2.0. According to Maxim, this new product makes it easy to add USB to any microprocessor.

Functions integrated within the MAX3420 include a ±15kV ESD-protected USB transceiver, a USB serial interface engine (SIE), endpoint buffer memory, an SPI slave interface, and a 1.5 kilohm D+ pullup resistor. The integrated USB transceiver features a programmable USB connect and disconnect, while the SIE handles low-level USB protocol details such as automatic NAK until ready, bit stuffing, CRC generation/checking, and bus retries.

The MAX3420E operates using a register set accessed by the SPI interface, which operates up

to 26MHz. Any SPI master (microprocessor, ASIC, DSP, etc.) can add USB functionality using the simple 3- or 4-wire interface. A programmable interrupt output can be used to reduce or eliminate microprocessor polling. Integrated logic-level translators allow the SPI interface to operate at a system voltage between 1.71V and 3.6V. Additionally, four general-purpose inputs and outputs allow any microprocessor that uses I/O pins to implement the SPI interface to reclaim those pins and gain additional ones.

The MAX3420E operates over the extended temperature range (-40°C to 85°C). This device is available in 7-by-7mm, 32-pin TQFP and 4-by-4mm, 24-pin TQFN packages. Prices start at $2.65 (1,000-up, FOB USA).