P2 - HDMI and Waveshare 5" display

Comments

• Wuerfel_21 Posts: 5,756

  2026-01-01 15:41

  Possible issues:

  • Display does not like the pin drive mode used (try replacing the line that says wrpin ##%001001<<8,#7<<6 + hdmi_base 'set 1k-ohm drive on HDMI pins with wrpin ##P_REPOSITORY|P_OE|P_LOW_FAST|P_HIGH_1K5|P_SYNC_IO, #hdmi_base addpins 7
  • Specialty display wants special resolutions (try this on a PC or something - does it actually take 640x480 modes?)
  • Some sort of exciting protocol incompatibility (not sure if chip's example is 100% spec compliant)
• Rayman Posts: 15,929

  2026-01-01 15:50

  What is display resolution?
  Looks like might be 800x480…
  That might require code tweaks
• Rayman Posts: 15,929

  2026-01-01 15:51

  Also it might be the 5v signal. Some displays seem to need it. The parallax adapter needs a jumper wire added to provide that…
• Wuerfel_21 Posts: 5,756

  2026-01-01 15:53

  Oh the 5V pin, that's the No. 1 thing to check actually. Some sinks will not turn on without that. Simple electrical fix.
• Rayman Posts: 15,929

  2026-01-01 16:22

  Here's an example of the jumper wire... Could also be a resistor instead of a jumper, like 1k or so...

  

  

  IMG_5511.jpeg

  480 x 640 - 213K

  IMG_5511.jpeg 212.5K
• Brian_B Posts: 844

  2026-01-01 18:04 edited 2026-01-01 18:04

  1080x1080 , but after i tried It with the 5 volt jumper wire it won't even work on the RPI.
• VonSzarvas Posts: 3,623

  2026-01-01 18:31 edited 2026-01-01 18:34

  The newer rev of the hdmi addon has pads labelled near the hdmi socket for adding a 1k resistor or jumper/shunt.

  BUT… first be sure that your breakout board is outputting 5V at the accessory headers.

  That usually means the breakout is powered by 5V (and not a higher voltage). And also that the breakout board has the 5V outputs enabled.

  To verify, measure the 5V output pin on the breakout board header before attaching the addon.