MOS Technology 6520
The MOS Technology 6520 is a Peripheral Interface Adapter (PIA) from MOS Technology in NMOS technology. It is a typical parallel I / O chip for 8-bit microprocessor systems of the 6500 and 6800 families.
Well-known PIA types are also z. B. the Motorola MC6820 and MC6821. The 6520 from MOS Technology is a functional replica of the MC6820, which was introduced in 1974 as part of the 6800 chip family . All PIA models are pin compatible and have the same functions but slightly different electrical properties. In most cases they can be exchanged directly for one another if the clock frequency is suitable. The PIA mostly come in a 40-pin DIP package . Functionally similar components of other processor families are the Z80 PIO and for Intel processors the Intel 8255 .
The PIA was designed to allow easy integration into bus systems around the Motorola 6800 and similar processors. It offers 20 I / O lines which are divided into 2 bidirectional 8-bit buses and 4 control lines. The 8-bit buses can also be used as 16 independent individual lines, i.e. H. The data direction can also be controlled individually for each bit using data direction registers . The control lines can be used to generate handshakes and interrupts , or they can simply deliver high or low levels.
PIA modules have been used in industrial control computers and single-board and home computers . PIA was the use in home computers known Atari 400 and 800 , in which he, the four joystick - Interfaces served, and the use in the electronics of many arcade and pinball slot machines and jukeboxes .
Due to the wide range of applications, PIA ICs were later produced by other manufacturers in addition to Motorola and MOS Technology, including Rockwell , Fairchild , AMI Semiconductor , Hitachi , Synertek , CMD and Western Design Center .
literature
- Lance A. Leventhal: 6502 Assembly Language Programming 2nd Edition . 2nd edition. Osborne / McGraw-Hill, Berkeley CA 1986, ISBN 0-07-881216-X .
