8051 Based TV Display
8051 Based TV Display: In the course of a recent 8052.com thread , using '51 variants as audio/video co-processors came up. In response, i spent last Sunday implementing a micro only solution for a modest 256 x 190 pixel monochrome video generator for an equally modest 5" monochrome TV. What resulted was a software based, bit-mapped, NTSC video generator.
Utimately intending to build a VGA class display around a '51 platform, the first step was a direct video television display in hopes of leaving a bit-mapped serial terminal behind.
As an initial platform, i re-used a DS80C420 equipped PCB, removing it's SPI serial chip and installing a "kludge DAC" to drive the TV. As this board had no provision for external XRAM memory, the 1kB SRAM, integrated into the microcontroller, was all that was available for Video RAM. A consequence of this is that the display format can be seen to repeat as this 1k is "looped" for display.
Quick Summary: The generation of this level of video is easily in the grasp of modern microcontrollers.
Available processor cycles occur with regular and predictable timing allowing additional tasks such as connected device interface and display formatting to also occur.