RTD Embedded Technologies, Inc.
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26
FPGA35S6046/FPGA35S6101 User’s Manual
The various modes are show in Table 19 below. The modes are selected using the com?_mode[2:0] signals in the FPGA. The Table then
shows the FPGA signal associated with each pin of the connector.
Table 19: Transceiver Configuration
RS-232
RS-485
RS-422
Dual RS-422
Dual RS-485
com?_mode[2:0]
= 001
com?_mode[2:0]
= 010
com?_mode[2:0]
= 011
com?_mode[2:0]
= 100
com?_mode[2:0]
= 111
CN Pin
FPGA Signal
Use
FPGA Signal
Use FPGA Signal
Use
FPGA Signal
Use
FPGA Signal
Use
1
com?_dcd
(RX) DCD
*
RXD2-
*
RXD4-
2
com?_dsr
(RX)
DSR
com?_rxd
(RX)
RXD2+
com?_dsr
(RX)
RXD4+
3
com?_rxd
(RX)
RXD
*
D-
*
TXD-
*
TXD1-
*
D1-
4
com?_rtd
(TX)
RTS
com?_dcd
(RX) RXD+
com?_dcd
(RX) RXD1+
com?_ri
(RX)
RXD2+
5
com?_txd
(TX)
TXD
*
RXD-
*
RXD1-
*
RXD2-
6
com?_cts
(RX)
CTS
com?_dcd
(RX)
com?_txd
(TX)
D+
com?_txd
(TX)
TXD+
com?_txd
(TX)
TXD1+
com?_dcd
(RX)
com?_txd
(TX)
D1+
7
com?_dtr
(TX)
DTR
com?_dtr
(TX)
TXD2+
com?_cts
(RX)
com?_dtr
(TX)
D2+
8
com?_ri
(RX)
RI
*
TXD2-
*
D2-
com?_dir1
‘1’ = D Transmitting
‘0’ = D Receiving
‘1’ = TXD enabled
‘0’ = TXD disabled
‘1’ = TXD1 en
abled
‘0’ = TXD1 disabled
‘1’ = D1 Transmitting
‘0’ = D1 Receiving
com?_dir2
‘1’ = TXD2 enabled
‘0’ = TXD2 disabled
‘1’ = D2 Transmitting
‘0’ = D2
Receiving
The other signals that are used to configure the transceivers are below:
com?_enable
: ‘1’ for normal operation, ‘0’ for shutdown mode
com?_slew
: ‘1’ for 250 kbps slew limiting, ‘0’ for full speed operation
com?_term
: ‘1’ to enable receiver term
ination (RS-
422/485 modes only), ‘0’ to disable termination
5.8
Embedded Digilent® USB JTAG Programmer
This FPGA board includes an embedded Digilent ® JTAG programming module. It connects to the host through the USB connections on the
PCIe Bus connectors. A USB hub is also provided for lane repopulation. The programming module is compatible with all Xilinx tools, including
iMpact and ChipScope (
).
It is also supported by Digilent’s Adept sof
tware package (
).
In order to use the embedded programmer, JP1 must be installed. This attaches the programmer to the JTAG chain. CN3 can always be used
regardless of whether or not JP1 is installed.
The embedded programmer has a user string of “RTD” followed by the serial number of the board. This can be use
d to differentiate the
programmers if there are multiple boards in the system.
