VolvoRTI/Raspberry/debugOscillo/Notes.md

1.8 KiB

Debug VGA param

Params for custom VGA

Modify file: sudo nano /boot/config.txt then restart to apply dpi_group=2 dpi_mode=87 dpi_timings= xxxx

Tests:

  • 640x480 60Hz : dpi_timings=640 0 16 96 48 480 0 11 2 31 0 0 0 60 0 25175000 1 Visible but only halph of the screen...
  • 320x240 60Hz : 'dpi_timings=320 1 12 32 44 240 1 6 10 6 0 0 0 60 0 6400000 1` Not working

Resolution:

  • 400x234

Syntax:

hdmi_timings=<h_active_pixels> <h_sync_polarity> <h_front_porch> <h_sync_pulse> <h_back_porch> <v_active_lines> <v_sync_polarity> <v_front_porch> <v_sync_pulse> <v_back_porch> <v_sync_offset_a> <v_sync_offset_b> <pixel_rep> <frame_rate> <interlaced> <pixel_freq> <aspect_ratio>

  • <h_active_pixels> = horizontal pixels (width)
  • <h_sync_polarity> = invert hsync polarity
  • <h_front_porch> = horizontal forward padding from DE acitve edge
  • <h_sync_pulse> = hsync pulse width in pixel clocks
  • <h_back_porch> = vertical back padding from DE active edge
  • <v_active_lines> = vertical pixels height (lines)
  • <v_sync_polarity> = invert vsync polarity
  • <v_front_porch> = vertical forward padding from DE active edge in horizontal sync pulse
  • <v_sync_pulse> = vsync pulse width in pixel clocks
  • <v_back_porch> = vertical back padding from DE active edge in horizontal sync pulse
  • <v_sync_offset_a> = leave at zero
  • <v_sync_offset_b> = leave at zero
  • <pixel_rep> = leave at zero
  • <frame_rate> = screen refresh rate in Hz
  • = leave at zero
  • <pixel_freq> = clock frequency (widthheightframerate)
  • <aspect_ratio> = *

HDMI_ASPECT_4_3 = 1
HDMI_ASPECT_14_9 = 2
HDMI_ASPECT_16_9 = 3
HDMI_ASPECT_5_4 = 4
HDMI_ASPECT_16_10 = 5
HDMI_ASPECT_15_9 = 6
HDMI_ASPECT_21_9 = 7
HDMI_ASPECT_64_27 = 8