Specifications

B–2 I/O Space Address Maps
Subject to Change – 17 January 1997
PCI Sparse I/O Space
B.2.1.1 FDC37C935 Combination Controller Register Address Space
Table B–1 lists the base address values for the SMC FDC37C935 combination
diskette, serial port, parallel port, keyboard, mouse, and TOY clock controller.
The general registers are located at addresses 398 (index address) and 399 (data
address). For example, writing an index value of 1 to address 398 selects the function
address register. If a read operation from address 399 follows, the data associated
with the function address register is returned. If a write operation to address 399
follows, the function address register will be updated.
Table B–1 Combination Controller Register Address Space Map
Address Offset
Read/Write Physical Address Register
General Registers
398 85.8000.7300 Index address
399 85.8000.7320 Data address
Index Register
0 Function enable
1 Function address
2 Power and test
COM2 Serial Port Registers
2F8-R
0DLAB=0
85.8000.5F00 COM2 receiver buffer
2F8-W
0DLAB=0
85.8000.5F00 COM2 transmitter holding
2F8 0DLAB=1 85.8000.5F00 COM2 divisor latch (LSB)
2F9 1DLAB=0 85.8000.5F20 COM2 interrupt enable
2F9 1DLAB=1 85.8000.5F20 COM2 divisor latch (MSB)
2FA-R 85.8000.5F40 COM2 interrupt identification
2FA-W 85.8000.5F40 COM2 FIFO control
2FB 85.8000.5F60 COM2 line control
2FC 85.8000.5F80 COM2 modem control
2FD 85.8000.5FA0 COM2 line status