I am working on setting up a TMS9918ANL Video Display Processor. I was wondering if there is any way I can test to see if it is working without having the DRAM hooked up (I have a while before the DRAM arrives in the mail lol). If you could tell me how to hook it up so I can make sure it is functional (Ex. Just to give a black screen on composite out) I would appreciate it :)

1 Answer 1


Well, if the remaining circuitry is done, you may want to simply put pulldowns at the read data input pins. With the chip programmed as usual this should produce an all black frame.

  • While not displaying much on a CRT it should at least synchronize.
  • Some Chinese analogue/HDMI converter should as well report synchronisation (and display a scaled up black picture).
  • Last but not least, it should be rather easy to show the frames using an oscilloscope.

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