The overview information for the 68HC11 family of microcontrollers is included on this CD for your convenience. For specific information, please see CD1 of this CDROM set.

68HC11 CPU and Peripheral Overview

Click on any block diagram to enlarge

68HC11 Central Processor Unit (CPU11)

  • Up to 5 MHz bus operation at 5 V
  • Up to 3 MHz bus operation at 3 V
  • Two 8-bit or one 16-bit accumulator
  • Two 16-bit index registers
  • 16-bit stack pointer
  • Powerful bit-manipulation instructions
  • Six powerful addressing modes (Immediate, Direct, Extended, Indexed, Inherent, and Relative)
  • Memory mapped I/O and special functions
  • 16 x 16 integer and fractional divides
  • 8 x 8 multiply
  • Power-saving stop and wait modes

    • Byte Erasable EEPROM Memory
    Most derivatives of the 68HC11 Family feature on-chip byte-erasable EEPROM for enhanced programming flexibility with no separate supply voltage required. This integrated non-volatile memory solution enables:

  • Storage of calibration information
  • Self-adjusting or self-adapting systems
  • Data logging for historical or secure data
  • Jump tables and code patches

    • Expanded Bus Memory Interfaces
    In many applications, the 68HC11 provides a single-chip solution. All family derivatives are also expandable for the incorporation of external memory in the design.

  • Standard 64 Kbyte addressing space
  • Some 68HC11s have up to 1 Mbyte addressing space
  • Either multiplexed or non-multiplexed interfaces

    • Serial Peripheral Interface (SPI)
    The SPI communicates synchronously over short distances (usually on a single PCB) at high speed. The SPI allows the microcontroller to communicate with peripheral devices such as a simple shift register, a serial EEPROM, or a complete LCD or ADC subsystem.

  • Full-duplex, three-wire synchronous transfers
  • Master or slave operation
  • Maximum master bit frequency is bus frequency divided by 2
  • Maximum bit rate of 2 MHz for a 4 MHz system clock
  • Maximum slave bit frequency is bus frequency
  • Maximum bit rate of 4 MHz for a 4 MHz system clock
  • Four programmable master bit rates
  • Programmable clock polarity and phase
  • End of transmission interrupt flag

    • Serial Communications Interface (SCI)
    The SCI is a serial UART-type asynchronous communications system. The SCI can be used for communications between the microcontroller and a terminal, a computer, or a microcontroller network. A typical SCI application is long-distance communications (RS-232).

  • Standard mark/space non-return-to-zero format
  • Full-duplex operation
  • Double buffering of both transmitter and receiver
  • Separately enabled transmitter and receiver
  • Programmable 8-bit or 9-bit character length
  • Advanced error detection at 1/16 of a bit time
  • Baud rate generator with programmable baud rates
  • Idle line and address mark wakeup methods
  • Receiver framing error detection
  • Break send capability
  • Optional hardware parity checking and generation
  • Separate transmitter, receiver, and error interrupt vectors

    • Low-Power Operation
    The 68HC11 provides high performance at low power with supply voltages ranging from 3 V to 5.5 V. Further power reductions can be achieved by some devices which have a Phase-Locked Loop (PLL) clock synthesizer circuit. The PLL allows clock speed reduction by switching the internal clock to a lower, power-saving frequency.


    High Performance Timer
    The industry standard 68HC11 timer provides flexibility, performance, and ease of use. The system is based on a free-running, 16-bit counter with a programmable prescaler, overflow interrupt, and separate function interrupts.

    Additional 68HC11 timer features include:

  • Multiple input capture functions and multiple output compares
  • Real-time periodic interrupts
  • Computer Operating Properly (COP) watchdog protection against software failures
  • Pulse accumulator for external event counting or gated time accumulation
  • An optional PWM offering up to six channels and up to 16-bit PWM outputs
  • Optional event counter system for advanced timing operations

    • Analog-to-Digital Converter (ADC)
    The ADC periodically samples external analog signals and produces corresponding digital values. Typical applications are measuring analog inputs like battery voltage, temperature, pressure, and fluid levels.
  • Linear successive approximation
  • 8-bit or 10-bit resolution
  • Single or continuous conversion modes
  • Multiple result registers
  • Selectable ADC clock
  • Analog multiplexer allows variable number of channels with a single ADC

    • Pulse-Width Modulation
    The 68HC11 Family offers a selection of Pulse-Width Modulation (PWM) options to support a variety of applications. Up to six PWM channels can be selected to create continuous waveforms with programmable rates and software selectable duty cycles from 0 to 100%.



    68HC11 Product Overview

    Within the 68HC11 Family, there are six major series of microcontroller units, each composed of many related devices. The following are examples of the features the 68HC11 can offer as shown through specific devices within each series.

    68HC11 D Family:
    The 68HC11D3 chip with 4 Kbytes ROM offers an economical alternative for applications when advanced 8-bit performance is required with fewer peripherals and less memory.

    68HC11 E Family:
    This series contains extremely flexible I/O capability that allows facilities to be configured to best match the application. It was the first in the family to combine EEPROM and EPROM on a single chip. The E-series offers multiple memory sizes in a pin-compatible package.

    68HC11 F Family:
    The 68HC11 F Family stands out with its extra I/O ports, an increase in static RAM (1 Kbyte), chip selects, and a 5 MHz non-multiplexed bus.

    68HC11 K Family:
    Of the very high performance 68HC11 devices, the 68HC11K4 and 68HC11KW1 offer high speed, an MMU (Memory Management Unit), PWMs, and plenty of I/O.

    68HC11 KS Family:
    Similar to the K Family, these devices offer high performance, large on-chip memories, and an additional power-saving mode in lower pin count packages.

    68HC11 P Family:
    The 68HC11P2 offers a power-saving, programmable, PLL-based clock circuit along with many I/O pins, large memory, and 3 SCI ports.

    All 68HC11 Family members have on-chip SCI and SPI, and most have EEPROM and an ADC.



    68HC11 Development Tools Overview

    The 68HC11 Family is supported by dozens of independent development tool suppliers with a variety of hardware and software development tools including: in-circuit emulators, logic analyzers, programmers, evaluation boards, C compilers, assemblers, debuggers, simulators, real-time operating systems - all allowing designers to efficiently develop, monitor, test, and debug code to get applications up and running fast.

    68HC11 Evaluation Boards (EVB/EVBU)
    The 68HC11 Evaluation Board (EVB) and Universal Evaluation Board (EVBU) are economical boards for evaluating code destined for the MC68HC11E9, MC68HC711E9, and MC68HC811E2 microcontrollers.

    The EVB comes with an on-board MC68HC11A8, and the EVBU comes with an on-board MC68HC11E9. These boards feature:

  • The BUFFALO ROM monitor program
  • Either expanded mode of operation, with full bus access for debugging and evaluation (EVB), or single-chip (I/O only) mode of operation (EVBU)
  • Built-in RS-232C I/O port circuitry
  • Wire-wrap area (EVBU) for MCU custom interfacing

    • 68HC11 Evaluation System (EVS)
    The 68HC11 Evaluation System (EVS) supports the design, debugging, and evaluation efforts necessary for developing target systems based on an 68HC11 microcontroller, letting developers generate, execute, and debug code.

    Users can either generate code with a resident on-line assembler or download the code from an external terminal into the EVS's user-evaluation RAM. The microcontroller I/O expansion port facilitates easy connection to the target system, and users can add a separately purchased logic analyzer for external hardware trace of code execution.

    MMDS11 Modular Development System
    The MMDS11 features high-speed, non-intrusive in-circuit emulation, real-time read/write memory, and bus state analysis for debugging hardware and software. It also has an integrated development environment that substantially speeds development and debugging tasks.

    SPGMR11 Serial Programmer
    The SPGMR11 programs 68HC11 Family devices that contain an EPROM or EEPROM array, using plug-in programming adapters to accommodate a variety of MCU devices and packages. An on-board programming-voltage circuit eliminates the need for an external 12 V supply.