Hello,
Hi, I am experimenting with differential outputs on the Arty A7. For this, I am using the 100MHz clock and have instantiated an ODDR then OBUFDS -- . I Have also looked through the 7-series Select-IO Resources User Guide and the only differential I/O at 3.3V is TMDS_33 IOStandard.
OBUFDS #(
.IOSTANDARD("TMDS_33") // Specify the input I/O standard
)OBUFDS_inst (
.O(buff_out_p), // Diff_p output (connect directly to top-level port)
.OB(buff_out_n), // Diff_n output (connect directly to top-level port)
.I(buff_local) // Buffer input
);
The .xdc file has the following --
## Pmod Header JB set_property -dict { PACKAGE_PIN E15 IOSTANDARD TMDS_33 } [get_ports { buff_out_p }];
set_property -dict { PACKAGE_PIN E16 IOSTANDARD TMDS_33 } [get_ports { buff_out_n }];
Pins E15/E16 are HR I/O banks [JB1/2] and they should work fine.
Synthesis & implementation are fine and I can generate a bitstream, but I see no output on these pins (just 0v)
I also tried to connect a termination resistor of 50 ohm pulled up to 3.3 V as recommended for FP_3.3_50 [OFF chip termination]. but it gives nothing...can anyone help me in this?
Question
qamesh
Hello,
Hi, I am experimenting with differential outputs on the Arty A7. For this, I am using the 100MHz clock and have instantiated an ODDR then OBUFDS -- . I Have also looked through the 7-series Select-IO Resources User Guide and the only differential I/O at 3.3V is TMDS_33 IOStandard.
ODDR #(
.DDR_CLK_EDGE("SAME_EDGE"),
.INIT(1'b0),
.SRTYPE("SYNC")
)ODDR_CLKADC(
.Q(buff_local),
.C(buff_in),
.CE(1'b1),
.D1(1'b1),
.D2(1'b0),
.R(1'b0),
.S(1'b0)
);
OBUFDS #(
.IOSTANDARD("TMDS_33") // Specify the input I/O standard
)OBUFDS_inst (
.O(buff_out_p), // Diff_p output (connect directly to top-level port)
.OB(buff_out_n), // Diff_n output (connect directly to top-level port)
.I(buff_local) // Buffer input
);
The .xdc file has the following --
## Pmod Header JB
set_property -dict { PACKAGE_PIN E15 IOSTANDARD TMDS_33 } [get_ports { buff_out_p }];
set_property -dict { PACKAGE_PIN E16 IOSTANDARD TMDS_33 } [get_ports { buff_out_n }];
Pins E15/E16 are HR I/O banks [JB1/2] and they should work fine.
Synthesis & implementation are fine and I can generate a bitstream, but I see no output on these pins (just 0v)
I also tried to connect a termination resistor of 50 ohm pulled up to 3.3 V as recommended for FP_3.3_50 [OFF chip termination]. but it gives nothing...can anyone help me in this?
grammar mistake
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