XR17V258 Datasheet, PDF (36/70 Pages) Exar Corporation – 66MHZ PCI BUS OCTAL UART WITH POWER MANAGEMENT SUPPORT

XR17V258
66MHZ PCI BUS OCTAL UART WITH POWER MANAGEMENT SUPPORT
FIGURE 14. INTERNAL LOOP BACK
xr
REV. 1.0.0
VCC
Transmit Shift
Register
MCR bit-4=1
Receive Shift
Register
VCC
RTS#
CTS#
DTR#
VCC
DSR#
RI#
CD#
OP1#
OP2#
TX [7:0]
RX [7:0]
RTS# [7:0]
CTS# [7:0]
DTR# [7:0]
DSR# [7:0]
RI# [7:0]
CD# [7:0]
4.5 UART CHANNEL CONFIGURATION REGISTERS AND ADDRESS DECODING
The 8 sets of UART configuration registers are decoded using address lines A9 to A11 as shown below.
Address lines A0 to A3 select the 16 registers in each channel. The first 8 registers are 16550 compatible with
EXAR enhanced feature registers located on the upper 8 addresses.
A11 A10
0
0
0
0
0
1
0
1
1
0
1
0
1
1
1
1
A9
UART CHANNEL
SELECTION
0
0
1
1
0
2
1
3
0
4
1
5
0
6
1
7
36