PC87108AVHG Datasheet, PDF (1/56 Pages) National Semiconductor (TI) – Advanced UART and Infrared Controller

PRELIMINARY
August 1998
PC87108AVHG/PC87108AVJE
Advanced UART and Infrared Controller
General Description
The PC87108A is a serial communications device with infra-
red capability. It supports 6 modes of operation and is back-
ward compatible with the 16550 and 16450. The operational
modes are: UART, Sharp-IR, IrDA 1.0 SIR, IrDA 1.1 MIR and
FIR, and Consumer Electronics IR (also referred to as TV
Remote or Consumer Remote Control).
The device provides two methods to allow its internal regis-
ters to be accessed. It can either directly decode a 16-bit ad-
dress, or it can accept an externally generated chip select in
combination with a 4-bit address. When a 16-bit address is
used, any one of four PC COMM port legacy addresses can
be selected as the base address.
In order to support existing legacy software based upon the
16550 UART, the PC87108A provides a special fallback
mechanism that automatically switches the device to 16550
compatibility mode when the baud generator divisor is ac-
cessed through the legacy ports in bank 1.
The device architecture has been optimized to meet the re-
quirements of a variety of UART and infrared based applica-
tions. DMA support for all operational modes has been incor-
porated into the architecture. Routing for interrupt and DMA
handshake signals is provided to meet Plug-and-Play as well
as PC’ 95 requirements.
The device can use either 1 or 2 DMA channels. One chan-
nel is required for infrared based applications, since infrared
communications work in half duplex fashion. Two channels
would normally be needed to handle high-speed full duplex
UART based applications.
To further ease driver design and simplify the implementa-
tion of infrared protocols, a 12-bit timer with 125 µs resolu-
tion has also been included.
Features
n Fully compatible with 16550 and 16450 devices
n Extended UART mode
n Sharp-IR with selectable internal or external modulation/
demodulation
n IrDA 1.0 SIR with up to 115.2 kbaud data rate
n IrDA 1.1 MIR and FIR with 0.576, 1.152 and 4.0 Mbps
data rates
n CEIR mode
n UART mode data rates up to 1.5 Mbps
n Back-to-Back infrared frame transmission and reception
n Full duplex infrared frame transmission and reception
n Transmit deferral
n Automatic fallback to 16550 compatibility mode
n IrDA modes pipelining
n Selectable 16 or 32 level FIFOs
n Support for Plug-n-Play infrared adapters
n Automatic or manual transceiver configuration
n 12-bit timer for infrared protocol support
n 4 general purpose I/O pins
n Interrupt signal routing to 1 of 7 output pins
n DMA handshake signal routing for either 1 or 2 channels
n Full 16-bit address decode
n Selectable base address or chip select mode
n Support for power management
n 5V or 3.3V operation
n ISA compatible interface
n 80-pin PQFP or TQFP package
Block Diagram
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