New Features Interrupt Single Step Extensions Instruction Set expanded to 60 instructions Program memory expanded to 8K bytes Registers expanded to 24 Subroutine stack expanded to 7 levels deep New Support chips 4201 - Clock Generator 4308 - 1K byte ROM 4207 - General Purpose byte Output port 4209 - General Purpose byte Input port 4211 - General Purpose byte I/O port 4289 - Standard Memory Interface (replaces 4008/4009) 4702 - 256 byte UVEPROM 4316 - 2K byte ROM 4101 - 256 4-bit word RAM See also List of Intel microprocessors