NEC µPD7220
Encyclopedia
The High-Performance Graphics Display Controller 7220 (commonly µPD7220) is a video interface controller developed by NEC
and used among others in its APC III
computers and the Epson QX-10
.
A CMOS variant is called µPD72020.
Writing to the 7220 uses both registers; A1 for writing the command, A0 for writing the parameters to the queue.
NEC
, a Japanese multinational IT company, has its headquarters in Minato, Tokyo, Japan. NEC, part of the Sumitomo Group, provides information technology and network solutions to business enterprises, communications services providers and government....
and used among others in its APC III
APC III
The APC III was released by NEC in 1983. The APC III was based upon the Intel 8086 processor, with superior specifications to the IBM PC....
computers and the Epson QX-10
Epson QX-10
The Epson QX-10 is a microcomputer running CP/M or TPM-III which was introduced in 1983. It was based on a Zilog Z80 microprocessor, running at 4 MHz, provided up to 256K of RAM organized in four switchable banks, and included a separate graphics processor chip manufactured by NEC to provide...
.
A CMOS variant is called µPD72020.
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.