PC87309 Datasheet, PDF (102/192 Pages) National Semiconductor (TI) – PC87309 SuperI/O Plug and Play Compatible Chip in Compact 100-Pin VLJ Packaging

Enhanced Serial Port with IR -UART2 (Logical Device 2)
5.0 Enhanced Serial Port with IR -
UART2 (Logical Device 2)
This module provides advanced, versatile serial communi-
cations features with infrared capabilities. It supports four
modes of operation: UART, Sharp-IR, IrDA 1.0 SIR (hereaf-
ter called SIR) and Consumer-IR (also called TV-Remote or
Consumer remote-control). In UART mode, the module can
function as a standard 16450 or 16550, or as an Extended
UART.
Existing 16550-based legacy software is completely and
transparently supported. Module organization and specific
fallback mechanisms switch the module to 16550 compati-
bility mode upon reset or when initialized by 16550 soft-
ware.
You can configure this module for either partial or full infra-
red communication support, as follows:
l Mode 1: Full-IR Mode (CFG0 = 0)
Fully IR-compliant device only. All the UART compli-
ance pins of UART2 are not available (i.e. the outputs
are not routed and the inputs are assumed inactive).
Any attempt to work with the port as a UART in this
mode has no effect.
l Mode 2: Two-UART Mode (CFG0 = 1)
Works as UART or as partially IR-compliant device. The
IR interface includes only two signals, IRTX and IRRX1.
The IRSL2-0 pins and ID3-0 inputs are not available in
this mode. Any attempt to work with IRRX2 and/or to
manipulate IRSL2-0 in this mode has no effect.
This module does not recognize the operation mode, and
there is no hardware protection against invalid usage or
configuration. The software must therefore avoid any invalid
operation of the UART2 in either one of these two modes.
This module includes two DMA channels; the device can
use either 1 or 2 of these channels. One channel is required
for infrared-based applications, since infrared communica-
tion works in half duplex fashion. Two channels would nor-
mally be needed to handle high-speed full duplex UART
based applications.
5.1 FEATURES
q _{Fully compatible with 16550 and 16450 devices}
q _{Automatic fallback to 16550 compatibility mode}
q _{Extended UART mode}
q _{UART baud rates up to 1.5 Mbps}
q _{Sharp-IR with selectable internal or external modula-}
tion/demodulation
q _{IrDA 1.0 SIR with data rates up to 115.2 Kbps}
q _{Consumer-IR (TV-Remote) mode}
q _{Full duplex infrared capability for diagnostics}
q _{Transmission deferral (in Consumer-IR mode)}
q _{Selectable 16-level transmission and reception FIFOs}
(RX_FIFO & TX_FIFO respectively)
q _{Multiple optical transceiver support}
q _{Automatic or manual transceiver configuration}
q _{Support for Plug-n-Play infrared adapters}
5.2 FUNCTIONAL MODES OVERVIEW
This multi-mode module can be configured to act as any
one of several different functions. Although each mode is
unique, certain system resources and features are common
to some or to all modes.
5.2.1 UART Modes: 16450 or 16550, and Extended
UART modes support serial data communications with a re-
mote peripheral device or modem using a wired interface.
The device transmits and receives data concurrently in full-
duplex operation, performing parallel-to-serial and serial-to-
parallel conversion and other functions required to ex-
change parallel data with the system. It also interfaces with
external devices using a programmable serial communica-
tions format.
The following UART modes are supported:
q _{16450 or 16550 mode (Non-Extended modes)}
q _{Extended mode}
The 16450 or 16550 mode is functionally and software-
compatible with the standard 16450 or 16550 UARTs. This
is the default mode of operation after power up, after reset
or when initialized by software written for the 16450 or
16550 UART (Special mechanisms switch the module auto-
matically to 16550 UART mode when standard 16550 soft-
ware is run).
The 16550 UART mode has all the features of the 16450
mode, with the addition of 16-byte data FIFOs for more effi-
cient data I/O.
In Extended mode, additional features become available
that enhance the UART performance, such as additional in-
terrupts and DMA ability (see “Extended UART Mode” on
page 104).
The UART supports baud rates of up to 115.2 Kbps in 16450
or 16550 mode, and up to 1.5 Mbps in Extended mode.
5.2.2 Sharp-IR, IrDA SIR Infrared Modes
The Sharp-IR mode provides bidirectional communication
by transmitting and receiving infrared radiation. In this
mode, infrared I/O circuits was added to the UART, which
operates at 38.4 Kbps in half-duplex, using normal UART
serial data formats with Digital Amplitude Shift Keying
(DASK) modulation. The modulation/demodulation can be
operated internally or externally.
In SIR mode, the system functions similarly to the Sharp-IR
mode, but at 115.2 Kbps.
5.2.3 Consumer IR Mode
Consumer-IR mode supports all the protocols presently
used in remote-controlled home entertainment equipment:
RC-5, RC-6, RECS 80, NEC and RCA. The serial format is
not compatible with UART operation, and specific circuitry
performs all the hardware tasks required for signal condi-
tioning and formatting. The software is responsible for the
generation of the infrared code to be transmitted, and for the
interpretation of the received code.
5.3 REGISTER BANK OVERVIEW
Eight register banks, each containing eight registers, con-
trol UART operation. All registers use the same 8-byte ad-
dress space to indicate offsets 00h through 07h, and the
active bank must be selected by the software.
www.national.com
102