Intel EN87C196KC20: An In-Depth Technical Overview of the 16-Bit Embedded Controller
The Intel EN87C196KC20 stands as a significant milestone in the evolution of 16-bit embedded controllers, representing the high-performance pinnacle of the MCS® 96 family. This microcontroller was engineered for applications demanding complex real-time control, high-speed data acquisition, and robust computational power, making it a cornerstone in industrial automation, automotive systems, and advanced instrumentation during its era.
At its core, the EN87C196KC20 is built upon a 16-bit CHMOS CPU architecture that eliminates the classical accumulator bottleneck. Instead, it employs a register-to-register-based design centered around a 256-byte register file, where any register can function as an accumulator. This architectural choice significantly enhances operational speed and coding efficiency. The CPU can manipulate bits, bytes, words, and even double-words, and features a hardware multiplier/divider unit, enabling it to execute a 16x16-bit multiplication in just 1.75 µs and a 32/16-bit division in 3.0 µs (at 16MHz), which was remarkable for its time.
A key feature of this controller is its integrated 16KB of On-Chip EPROM. This non-volatile memory is used for storing the application firmware and is UV-erasable, allowing for prototype development and program iteration. Complementing this is 512 bytes of register RAM, which provides fast, on-chip storage for frequently accessed variables and stack operations, drastically reducing the need to access slower external memory.
The device's extensive Peripheral Transaction Server (PTS) deserves special attention. The PTS is a sophisticated dedicated interrupt handling microcoded controller that functions like a miniature DMA (Direct Memory Access) unit. It can service peripheral interrupts—such as those from timers or serial ports—with minimal CPU overhead, drastically improving system responsiveness in interrupt-heavy real-time environments.
For input/output capabilities, the EN87C196KC20 is exceptionally well-equipped. It includes a 10-Channel, 10-Bit Analog-to-Digital Converter (ADC) with a minimum conversion time of 22 µs, allowing it to interface directly with a multitude of analog sensors. Its High-Speed I/O Subsystem can independently measure pulse widths and generate pulses without CPU intervention. Furthermore, it features two standard serial ports (UART) and five 8-bit I/O ports, providing immense flexibility for connecting to other digital peripherals and communication networks.
Operating at a clock frequency of 16 MHz, the controller delivers a high level of performance. It is housed in an 68-pin PLCC (Plastic Leaded Chip Carrier) package, a common form factor that balances pin count with board space efficiency. The "C" in its part number signifies its construction using CHMOS technology, which offers the high speed of HMOS with the low power consumption of CMOS, making it suitable for power-sensitive applications.
ICGOOODFIND: The Intel EN87C196KC20 is a quintessential high-integration 16-bit microcontroller from a defining era of embedded systems. Its powerful register-based CPU, substantial on-chip memory, advanced PTS interrupt system, and rich suite of peripherals—including a high-speed ADC—made it an indispensable component for complex, real-time control systems, leaving a lasting legacy in embedded design philosophy.
Keywords: 16-Bit Embedded Controller, MCS® 96 Family, Peripheral Transaction Server (PTS), On-Chip EPROM, Integrated ADC.
