designation μPD72020. A follow-on project produced the μPD72120 Advanced Graphics Display Controller (AGDC) which was faster and supported a 16-bit interface. It was named one of the "Top 100" products of 1987 by Electronics Design. Internals Two I/O channels are used, addressing A0 and A1. Reading A0 retrieves the 7220 status. Reading A1 fetches the first byte from the internal queue. Writing to the 7220 uses both registers; A1 for writing the command, A0 for writing the parameters to the queue. The parts had an 8-bit data path. Parts were available with clocks running from 4 MHz to 5.5 MHz, which was considered relatively high-performance for the time. References External links uPD7220/uPD7220A User Manual, December 1985 Source code of driver for CP/M-86 7220 and 72020 data sheets (in Japanese) Graphics processing units Graphics chips muPD07220