PC87307VUL National Semiconductor, PC87307VUL Datasheet - Page 136

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

www.national.com
7.3 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.
The register bank organization enables access to the banks
as required for activation of all module modes, while main-
taining transparent compatibility with 16450 or 16550 soft-
ware, which activates only the registers and specific bits
used in those devices. For details, See Section 7.4.
The Bank Selection Register (BSR) selects the active bank
and is common to all banks. See Figure 7-1. Therefore,
each bank defines seven new registers.
The default bank selection after system reset is 0, which
places the module in the UART 16550 mode. Additionally,
setting the baud rate in bank 1 (as required to initialize the
16550 UART) switches the module to a Non-Extended
UART mode. This ensures that running existing 16550 soft-
ware will switch the system to the 16550 configuration with-
out software modification.
Table 7-1 shows the main functions of the registers in each
bank. Banks 0-3 control both UART and infrared modes of
operation; banks 4-7 control and configure the infrared
modes only.
Offset 07h
Offset 06h
Offset 05h
Offset 04h
Offset 02h
Offset 01h
Offset 00h
LCR/BSR
BANK 0
FIGURE 7-1. Register Bank Architecture
BANK 1
BANK 2
BANK 3
BANK 4
BANK 5
BANK 6
16550 Banks
UART1 and UART2 (with IR) (Logical Devices 5 and 6)
BANK 7
Throughout
All Banks
Common
Register
136
Banks 0 and 1 are the 16550 register banks. The registers
Bank 2 contains the non-legacy Baud Generator Divisor
Bank 3 contains the Module Revision ID and shadow regis-
Bank 4 contains setup parameters for the Infra-red modes.
Bank 5 registers control infrared parameters related to the
Bank 6 registers control physical characteristics involved
Bank 7 registers are dedicated to Consumer-IR configura-
7.4 UART MODES – DETAILED DESCRIPTION
The UART modes support serial data communications with
a remote peripheral device or modem using a wired inter-
face.
Bank
0
1
2
3
4
5
6
7
in these banks are equivalent to the registers contained
in the 16550 UARTs and are accessed by 16550 soft-
ware drivers as if the module was a 16550. Bank 1 con-
tains the baud divisor ports. Bank 0 registers control all
other aspects of the UART function, including data
transfers, format setup parameters, interrupt setup and
status monitoring.
ports, and controls the extended features special to this
UART, that are not included in the 16550 repertoire.
These include DMA usage. See ”Extended UART
Mode” on page 137.
ters. The Module Revision ID (MRID) register contains
a code that identifies the revision of the module when
read by software. The shadow registers contain the
identical content as reset-when-read registers within
bank 0. Reading their contents from the shadow regis-
ters lets the system read the register content without re-
setting them.
logical system I/O parameters.
in infrared communications (e.g. pulse width selection).
tion and control.
UART
TABLE 7-1. Register Bank Summary
Mode
IR
Global Control and Status
Legacy Bank
Baud Generator Divisor,
Extended Control and Status
Module Revision ID and
Shadow Registers
IR mode setup
Infrared Control
Infrared Physical Layer
Configuration
Consumer-IR and Optical
Transceiver Configuration
Main Functions