Revision 1.1
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G
SuperI/O Module
(Continued)
4.8
This section briefly describes the following blocks that pro-
vide legacy device functions:
LEGACY FUNCTIONAL BLOCKS
Serial Port (SP), UART functionality.
Infrared Communication Port.
Notes
The Serial Port is similar to SCC1 in the National
PC87338 device.
The IR Communications Port is similar to SCC2 in the
National PC87338 device.
The description of each Legacy block includes a general
description, register maps, and bit maps. For more infor-
mation about legacy blocks, contact your National Semi-
conductor representative.
4.8.1
The generic SP supports serial data communication with a
remote peripheral device or modem using a wired inter-
face. The functional blocks can function as a standard
16450, 16550, or as an Extended UART.
UART Functionality (SP)
4.8.1.1
Four register banks, each containing eight registers, con-
trol UART operation. All registers use the same 8-byte
address space to indicate offsets 00h through 07h. The
BSR register selects the active bank and is common to all
banks. See Figure 4-18.
UART Mode Register Bank Overview
4.8.1.2
SP Register and Bit Maps for UART Function-
ality
The tables in this subsection provide register and bit maps
for Banks 0 through 3.
Figure 4-18. UART Mode Register Bank
Architecture
Bank 0
Bank 1
Bank 2
Bank 3
Offset 07h
Offset 06h
Offset 05h
Offset 04h
LCR/BSR
Offset 02h
Offset 01h
Offset 00h
Common
Register
Throughout
All Banks
16550 Banks
Table 4-31. Bank 0 Register Map
Offset
Type
Name
00h
RO
RXD.
Receiver Data Port
W
TXD.
Transmitter Data Port
01h
R/W
IER.
Interrupt Enable
02h
RO
EIR.
Event Identification (Read Cycles)
W
FCR.
FIFO Control (Write Cycles)
03h
W
LCR
1
.
Line Control
R/W
BSR
1
.
Bank Select
04h
R/W
MCR.
Modem/Mode Control
05h
RO
LSR.
Link Status
06h
RO
MSR.
Modem Status
07h
R/W
SPR.
Scratchpad
RO
ASCR.
Auxiliary Status and Control
1.
When bit 7 of this register is set to 1, bits [6:0] of BSR select the bank, as shown in Table 4-32.