PC87307VUL National Semiconductor, PC87307VUL Datasheet - Page 135

• Manufacturer Part Number: PC87307VUL
• Description: PC87307/PC97307 Plug and Play Compatible and PC97 Compliant SuperI/O
• Manufacturer: National Semiconductor

7.0 UART1 and UART2 (with IR)
This section describes the functionality of the Legacy UART
(16450/16550), Enhanced UART and the IR modes.
UART1 supports standard 16450/16550 mode.
UART2 supports standard 16450/16550, Enhanced UART
and IR modes.
UART1 implements a subset of UART2 functionality. It sup-
ports UART mode hard-wired communications, but does
not support IR communication. Therefore, all explanations
of IR communication in this section do not apply to UART1.
The UART module provides advanced, versatile serial com-
munications features with infrared capabilities. It supports
four modes of operation: UART, Sharp-IR, IrDA 1.0 SIR
(hereafter 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.
The module includes two DMA channels that can support all
operational modes. The device can use either 1 or 2 DMA
channels. One channel is required for infrared based appli-
cations since infrared communications work in half duplex
fashion. Two channels would normally be needed to handle
high-speed full duplex UART based applications.
7.1 FEATURES
•
•
•
•
•
•
•
•
•
•
•
•
•
Fully compatible with 16550 and 16450 devices
Automatic fallback to 16550 compatibility mode
Extended UART mode
UART baud rates up to 1.5 Mbps
Sharp-IR with selectable internal or external modula-
tion/demodulation
IrDA 1.0 SIR with data rates up to 115.2 Kbps
Consumer-IR (TV-Remote) mode
Full duplex infrared capability for diagnostics
Transmission deferral (in Consumer-IR mode)
Selectable 16 or 32-level transmission and reception
FIFOs (RX_FIFO & TX_FIFO respectively)
Multiple optical transceiver support
Automatic or manual transceiver configuration
Support for Plug-n-Play infrared adapters
(Logical Devices 5 and 6)
UART1 and UART2 (with IR) (Logical Devices 5 and 6)
135
7.2 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.
7.2.1
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:
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 137).
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.
7.2.2
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.
7.2.3
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.
•
•
16450 or 16550 mode (Non-Extended modes)
Extended mode
UART Modes: 16450 or 16550, and Extended
Sharp-IR, IrDA SIR Infrared Modes
Consumer IR Mode
www.national.com