99xx

One of the first true 16 bit microprocessors which competed effectively with minicomputers in interrupt-driven, signal processing applications; despite the very poor support from Texas Instruments, the TMS 9900 had the potential to surpass the 8086 in popularity; it was based on the central processing unit architecture of the 990 minicomputer family; 

N-Channel silicon gate MOS technology; three power supplies (-5V, +5V, +12V); three accessible registers (program counter, workspace pointer, status register); all other temporary information being stored in external read / write memory; 16-bit instruction word; 16 prioritized interrupts; 16 general purpose registers;

4 MHz

embedded version of 9900; single 5 V supply; actually a stand-alone microcomputer (includes on-chip ROM (2 Kbytes) and read / write memory (128 bytes)); the 9940 found use in many control applications that were not general purpose; compatible with all other 9900 family devices

special features: four priority interrupts
                         on-chip counter / timer
                         32 general-purpose I/O bits
                         on-chip memory
                                 2 KBytes of ROM
                                 128 Bytes of RAM
                         I/O expansion for 256 bits
                         various clock speeds available