GENERAL DESCRIPTION
The LPC47B27x* is a 3.3V PC98/PC99 compliant Super I/O controller. The LPC47B27x implements the LPC
interface, a pin reduced ISA bus interface which provides the same or better performance as the ISA/X-bus with a
substantial savings in pins used. The LPC47B27x provides fan control through two fan speed control output pins and
two fan tachometer input pins. It also provides 37 general purpose input/output (GPIO) pins, a dual game port
interface, MPU-401 MIDI support and ISA IRQ to Serial IRQ conversion.
The LPC47B27x incorporates a keyboard interface, SMSC's true CMOS 765B floppy disk controller, advanced digital
data separator, two 16C550A compatible UARTs, one Multi-Mode parallel port which includes ChiProtect circuitry plus
EPP and ECP, on-chip 12 mA AT bus drivers, one floppy direct drive support, and Intelligent Power Management
including PME support. The true CMOS 765B core provides 100% compatibility with IBM PC/XT and PC/AT
architectures in addition to providing data overflow and underflow protection. The SMSC advanced digital data
separator incorporates SMSC's patented data separator technology, allowing for ease of testing and use. Both on-
chip UARTs are compatible with the NS16C550A. The parallel port is compatible with IBM PC/AT architecture, as
well as IEEE 1284 EPP and ECP. The LPC47B27x incorporates sophisticated power control circuitry (PCC) which
includes support for keyboard, mouse and consumer infrared wake-up events. The PCC supports multiple low power-
down modes.
The LPC47B27x supports the ISA Plug-and-Play Standard register set (Version 1.0a) and provides the recommended
functionality to support Windows '95. The I/O Address, DMA Channel and hardware IRQ of each logical device in the
LPC47B27x may be reprogrammed through the internal configuration registers. There are 480 (960 for Parallel Port)
I/O address location options, a Serialized IRQ interface, and three DMA channels.
The LPC47B27x does not require any external filter components and is therefore easy to use and offers lower system
costs and reduced board area. The LPC47B27x is software and register compatible with SMSC's proprietary
82077AA core.
*The “x” in the part number is a designator that changes depending upon the particular BIOS used inside the specific chip. “2”
denotes AMI Keyboard BIOS and “7” denotes Phoenix 42i Keyboard BIOS.
SMSC LPC47B27x
- 7 -
Rev. 08-10-04
DATASHEET
SMSC [ SMSC CORPORATION ]
