PC104P-SIO4BX User Manual, Revision: 0
General Standards Corporation
8302A Whitesburg Drive Huntsville, AL 35802, Phone: (256) 880-8787
D23
Internal
Loopback Mode
When DCE/DTE Mode is enabled (Bit D31=1), this bit will automatically loopback the TxC/RxC,
TxD/RxD, and RTS/CTS signals internal to the board.
D22:21
RESERVED
D20:19
Cable TxD Output Control
Allows TxD output to be used as a general purpose output.
D20
D19
TxD Source
0
X
USC_TxD
1
0
Output ‘0’
1
1
Output ‘1’
D18:17
Cable TxAuxC Output Control
Defines the Clock Source for the TxAuxC signal to the IO connector.
D18
D17
TxD Source
0
0
Tristate
0
1
On-board Programmable Clock
1
0
Output ‘0’
1
1
Output ‘1’
D16:15
Cable DCD Output Source
D16
D15
Output Source
Notes
0
0
USC_DCD Output
USC_DCD field (D12:D11) must equal ‘11’
0
1
RTS Output
Rx FIFO Almost Full
1
0
‘0’
Drive low
1
1
‘1’
Drive Hi
D14:13
Cable RTS Output Source
D14
D13
Output Source
Notes
0
0
USC_CTS Output
USC_CTS field (D10:D9) must equal ‘11’
0
1
RTS Output
Rx FIFO Almost Full
1
0
‘0’
Drive low
1
1
‘1’
Drive Hi
