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smunaut / ice40-playground

Various iCE40 cores / projects to play around with (mostly targeted at the icebreaker)
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hub75 improve line scanning to reduce visual distortion / line jump effect #7

Closed zzaurak closed 5 years ago

zzaurak commented 5 years ago

To reduce visual line scanning jump effect between line 31 and 32 (caused by scanning the lines in each bank from top to bottom) i suggest to implement a zig-zag line scanning as @smunaut has already implemented as a quick test for N_ROWS=32: cores/hub75/rtl/hub75_scan.v @@ -101,31 +101,35 @@

-   assign bcm_row = row;
+   assign bcm_row = { 1'b0, row[4:1] } ^ ( row[0] ? 5'h1f : 5'h00 );
    assign bcm_go  = (fsm_state == ST_PAINT);

    // Frame Buffer pre loader
-   assign fb_row_addr = row;
+   assign fb_row_addr = { 1'b0, row[4:1] } ^ ( row[0] ? 5'h1f : 5'h00 );