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Timing violation on Tang Nano 9K? #2

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rhgndf opened this issue Nov 3, 2024 · 2 comments
Open

Timing violation on Tang Nano 9K? #2

rhgndf opened this issue Nov 3, 2024 · 2 comments

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@rhgndf
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rhgndf commented Nov 3, 2024

I keep getting wrong frame magics:

Frame magic: D676C5DC, framecounter: 01B5, pack_state: 00
Frame magic: AA7AC7B1, framecounter: 71D6, pack_state: 00
Frame magic: AA7AC7B1, framecounter: 71D6, pack_state: 00
Frame magic: DA1ACAB1, framecounter: 71B7, pack_state: 00
Frame magic: DA1ACAB1, framecounter: 71B7, pack_state: 00
Frame magic: 7CD0A011, framecounter: 7178, pack_state: 00
Frame magic: 7CD0A011, framecounter: 7178, pack_state: 00
Frame magic: C67DC6B1, framecounter: 01B9, pack_state: 00
Frame magic: C67DC6B1, framecounter: 01B9, pack_state: 00
Frame magic: DA7ACDD1, framecounter: 712A, pack_state: 00
Frame magic: DA7ACDD1, framecounter: 712A, pack_state: 00
Frame magic: DB7ACAB1, framecounter: C1BB, pack_state: E0
Frame magic: DB7ACAB1, framecounter: C1BB, pack_state: E0
Frame magic: 5A1AC011, framecounter: 076C, pack_state: 00
Frame magic: 5A1AC011, framecounter: 076C, pack_state: 00
Frame magic: BFB0CDB7, framecounter: 01BD, pack_state: 00
Frame magic: BFB0CDB7, framecounter: 01BD, pack_state: 00
Frame magic: BAEAC6C1, framecounter: 01A2, pack_state: C0
Frame magic: BAEAC6C1, framecounter: 01A2, pack_state: C0
Frame magic: BA7ACAB1, framecounter: 01BF, pack_state: 05
Frame magic: ABDAACB1, framecounter: F1C0, pack_state: 00
Frame magic: ABDAACB1, framecounter: F1C0, pack_state: 00
Frame magic: DA7ACAB1, framecounter: 01C1, pack_state: A9

The place and route also reports timing violations?

Max Frequency Summary:

NO. Clock Name Constraint Actual Fmax Logic Level Entity
1 data_pll/CLKOUT.default_gen_clk 50.996(MHz) 122.724(MHz) 4 TOP
2 div_5/CLKOUT.default_gen_clk 67.495(MHz) 45.834(MHz) 16 TOP

Any idea how to resolve this?

@rhgndf rhgndf changed the title Timing violation? Timing violation on Tang Nano 9K? Nov 3, 2024
@rhgndf
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rhgndf commented Nov 3, 2024

These values, along with enabling the 'open source' fifo gives 0 counter errors.

localparam HDMI_PLL_IDIV  = 0;
localparam HDMI_PLL_FBDIV = 7;
localparam HDMI_PLL_ODIV  = 4;
localparam DATA_PLL_IDIV  = 8;
localparam DATA_PLL_FBDIV = 10;
localparam DATA_PLL_ODIV  = 32;

@steve-m
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steve-m commented Dec 7, 2024

Yes, the Tang Nano 9K is the most tricky one due to the speed grade of the FPGA.
After I recently found a pipelined TMDS encoder optimized for the Gowin FPGAs, I switched to it with commit a9bc725. Now Fmax for the div_5 clock is 76.648 MHz.

Can you retry your test?

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