Plug and Play UART
TL16PNP100 Stand-alone Plug and Play Controller
Designers of PC expansion boards, including fax/modems, memory or graphics cards, can incorporate Plug and Play (PnP) capabilities with one of two new devices from Texas Instruments. The TL16PNP550, a Universal Asynchronous Receiver/Transmitter (UART), is the industry's first such device to include PnP capabilities. The TL16PNP100 is a controller which interfaces an add-in PC board to the capabilities of a plug and play operating system.
PnP defines a means for peripherals to communicate with a machine's BIOS and operating system to resolve resource conflicts with little or no user intervention. PnP works with existing bus architectures, has low implementation cost, and comes with widespread industry backing.
The TL16PNP550, PnP UART completes the serial-to-parallel and parallel-to-serial data conversions needed for a PC's serial port and complies with the PnP specification's Auto-Configuration Sequence. The PnP portion of the 'PNP550 has a simple three-pin interface to EEPROM memory where information needed during auto-configuration is stored. It also provides the board designer with a high degree of flexibility by including 10 interrupt pins. The UART portion of the 'PNP550 contains internal FIFOs that can buffer 16 bytes of information. By buffering received and transmitted characters, the device can reduce the level of CPU interrupts. It also has an auto flow control feature which reduces software overhead and increases system efficiency. In addition to the baud rate generator that exists in the UART, the 'PNP550 has a clock prescaler. This feature allows for an increased baud rate. Because of its high output current drive, the 'PNP550 does not need an external buffer for data and interrupt signals.
The 'PNP550 also features two bypass modes which will be significant as the industry transitions to PnP capabilities. In PnP bypass mode, the PnP capabilities are not used and the device functions as a stand-alone UART. In UART bypass mode, the 'PNP550 functions as a stand-alone PnP controller.
The TL16PNP100 stand-alone PnP controller, which supports two logical devices, is designed for use on a PC add-in board to provide PnP auto configuration. A cost effective solution, the PnP controller features a simple, three-pin interface to EEPROM memory where information needed during PnP's auto-configuration process is stored. The device interfaces directly to the PC's ISA/AT bus and will require no buffering for data or interrupt signals. The device decodes two I/O chip selects and routes two interrupts to one of six interrupt pins.
The TL16PNP550 and TL16PNP100 are available now from TI and its authorized distributors at a suggested resale price of $4.60 for the TL16PNP550FN, and $5.60 for the TL16PNP100FN per device in quantities of 1,000.
Device Description UART FIFO Size TL16C450 UART 1-byte TL16C451 UART plus parallel port 1-byte TL16C452 Dual UART plus parallel port 1-byte TL16C550B UART 16-byte TL16C550C UART plus hardware 16-byte autoflow control TL16C552A Dual UART plus parallel port 16-byte TL16C554 Quad UART 16-byte TL16PC564A UART plus PCMCIA 64-byte TL16C750 UART plus hardware 64-byte autoflow control TL16PNP550 UART plus plug and play controller 16-byte TL16PNP100 Stand-alone plug and play controller NAVol 12, Summer, 1995