The Oscam Nano uses the CDP 1864 for video output. For details on the CDP 1861 please see the data sheets for this chip or the 'summary' on the CDP 1861 page. The Oscam Nano controls the CDP 1864 via INP 4 to switch the display off, INP 1 to switch the display on and EF1 to indicate the display status. Colour functions of the CDP 1864 are NOT used.
The Oscam Nano firmware uses the CDP 1864 with a resolution of 64 x 32 with interrupt routine entry point at @8146 and display memory at @0F00-@0FFF. This means that every 'pixel' is actually 6 lines high which is 2 lines higher than when using a CDP 1861 with the same resolution.
The display status is an active low output signal occurring for a period of four horizontal cycles prior to the beginning and end of the 196 line display window. The signal is used by the firmware interrupt routine to indicate the last 'row' of the display area.