8. Serial Controller
ÛZIATECH
53
PROGRAMMABLE REGISTERS
There are seven registers for initializing and controlling each serial channel. The "Serial
Controller Register Addressing" table below shows the I/O port addressing for these
registers. COM1 is located at address 3F8-3FFh; COM2 is located at address 2F8-
2FFh.
Screen 1 of the BIOS SETUP utility allows you to disable COM1 and/or COM2 and free
up that address range for STD bus expansion.
Serial Controller Register Addressing
Address
Register
Operation
0xF8h (DIV=0)
Receive Buffer
Read
0xF8h (DIV=0)
Transmit Buffer
Write
0xF8h (DIV=1)
Divisor Latch LSB
Read/Write
0xF9h (DIV=0)
Interrupt Control
Read/Write
0xF9h (DIV=1)
Divisor Latch MSB
Read/Write
0xFAh
Interrupt Status
Read
0xFAh
FIFO Control
Write
0xFBh
Line Control
Read/Write
0xFCh
Modem Control
Read/Write
0xFDh
Line Status
Read
0xFEh
Modem Status
Read
0xFFh
Reserved
Note:
COM1 is located at address 3F8-3FFh; COM2 is located at address 2F8-2FFh.
ADDITIONAL INFORMATION
Refer to the
Standard Microsystems Corporation™ FDC37C665GT
data book for more
information on the serial controller operating modes. The data sheet is available
online at
http://www.smsc.com/main/catalog/fdc37c665gt.html
The data sheet is in Adobe Acrobat format (PDF). If you do not have the Acrobat
Reader, it is available on the Adobe Home Page at