Technical Note 083 describes how to interface the 2651 PCI to various other microprocessors, such as the 8080, 8085, Z80, 8048 and 6800 Descendants of the 2651/2661 serial communications chips are still sold as the Philips SC26 series. 2656 System Memory Interface The 2656 was specifically designed to augment, and interface with, the 2650 and make a 2-chip computer possible. It contained everything the 2650 lacked to make a complete computer: 2 KB 8-bit mask-programmed ROM program memory 128 bytes 8-bit RAM memory Clock generator with crystal or RC network Power-on reset Eight general purpose I/O pins The I/O pins could be used as an 8-bit I/O port or programmed to generate enable signals for extra RAM, ROM or I/O ports. This was achieved by mask-programming a Programmable Logic Array in the 2656. To develop and test the design before committing it to production, Philips sold the PC4000, a 2656 emulator board using PROMs and FPLAs to emulate the ROM and PLA in the 2656. Notes References Citations Bibliography External links 2650 Emulators Datasheet Signetics 2650 family CPU World Instructor 50 Old-computers.com Adaptable Board Computer development system complete with 1 KiB PipBug monitor and 512 bytes of RAM the 2650 at www.cpu-museum.com (archived) Electronics Australia 2650 board at yesterdaystechnology.com Signetics 2650: An IBM on a Chip retrospective at The CPUSHACK Museum (October 16, 2016) Zaccaria The Invaders at Museum of the Game A 2650 cross assembler is available from https://shop-pdp.net/index.php Early microcomputers Motorola NXP Semiconductors 8-bit microprocessors