Before revision: Specifications The 1861 chip could display 64 pixels horizontally and 128 pixels vertically, though by reloading the 1802's R0 DMA register via the required 1802 software controller program and interrupt service routine, the resolution could be reduced to 64×64 or 64×32 to use less memory than the 1024 bytes needed for the highest resolution (with each monochrome pixel occupying one bit) or to display square pixels.
After revision: (direct memory access)Specifications The 1861 chip could display 64 pixels horizontally and 128 pixels vertically, though by reloading the 1802's R0 DMA register via the required 1802 software controller program and interrupt service routine, the resolution could be reduced to 64×64 or 64×32 to use less memory than the 1024 bytes needed for the highest resolution (with each monochrome pixel occupying one bit) or to display square pixels.