XR17V258_08 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
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]
REV. 1.0.1
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
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