Phoebe 2100: VIDC20+ Video Controller

VIDC20+, also known as VIDC20 revision R, is the latest iteration of the design used in the RiscPC.
It has been redesigned for a 0.6µm feature size, compared to the original device's 1.1µm feature size.
Shrinking the IC allows it to operate at higher speeds: the pixel clock is now 200MHz, compared to the RiscPC's 100MHz.
The VIDC20+ is provided with 4Mbytes of dual-port EDO VRAM, soldered to the motherboard.
This combination is expected to achieve resolutions of 1280 x 1024 at 75Hz refresh in 32,000 colours. It may be possible to achieve 1600 x 1200 in 32,000 colours, or 1280 x 1024 in 16 million colours.
The redesign for 0.6µm was carried out by Cirrus Logic, as part of the ARM7500FE development. A cut-down version of the VIDC20, the VIDC2L, was produced for the integrated processor; the revision R was a by-product of that work.