Electronic Design

Serial Legacy UART Provides Single-Chip USB Solution

Engineers can upgrade older RS232 designs to USB applications with a single-chip, cost-effective UART IC. This chip, the FT8U232AM, requires minimal development time and cost.

The FT8U232AM has data-transfer rates up to 920 (RS-232) and 2000 kbaud (RS-422/RS-485). Its 32-pin, 7- by 7-mm QFP combines ultra-high performance with the USB's ease of use. Also, its flexible architecture lets designers use it in USB modems, legacy RS-232-to-USB converter cables, USB interface cables for PDAs, RS-422 data links and instrumentation, and other applications.

Many manufacturers with RS-232-based peripherals need to convert to USB as painlessly as possible. Traditionally, engineers would redesign their products with a dedicated USB microcontroller. This requires extensive firmware development while sourcing or developing specific USB drivers for Windows 98/NT/2000 and iMAC operating systems. Instead, companies now can replace the RS-232 level-converter IC by dropping the FT8U232AM right into their products. Driver ICs are freely provided by the device's manufacturer.

This IC features a 384-byte receive buffer and a 128-byte transmit buffer for high data throughput, full hardware-assisted X-on/off handshaking, and support for event characters and line-break conditions. It also has an integrated 6- to 48-MHz clock multiplier circuit for FCC and CE compliance. Furthermore, it complies with the USB 1.1 specification.

Operating from a single supply of 4.4 to 5.25 V, the FT8U232AM requires no external regulator. An integrated 3.3-V regulator is included. Virtual COM-port drivers are available for Windows 98/NT/2000 and iMAC operating systems. Drivers for other operating systems, such as the Millennium, are under development.

The FT8U232AM is sampling now, and it will be available in production quantities in the third quarter. It costs $3.00 each in 1000-unit quantities.

Saelig Co. LLC, 1193 Moseley Rd., Victor, NY 14564; (716) 425-3753; www.saelig.com.

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