The Freescale 683xx is a family of compatible microcontroller

Microcontroller

A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...

s that use a Freescale 68000-based CPU

Central processing unit

The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

 core. The family was designed using a Hardware Description Language

Hardware description language

In electronics, a hardware description language or HDL is any language from a class of computer languages, specification languages, or modeling languages for formal description and design of electronic circuits, and most-commonly, digital logic...

, making the parts synthesizable, and amenable to improved fabrication processes, such as die shrinks.

There are two CPU cores used in the 683xx family: the 68EC000 and the CPU32. The instruction set of the CPU32 core is similar to the 68020 without bitfield instructions, and with a few instructions unique to the CPU32 core, such as table lookup and interpolate instructions, and a low-power stop mode.

The modules of the microcontroller were designed independently and released as new CPUs could be tested. This process let the architects perform "design-ahead" so that when silicon technlogies were available, Motorola had designs ready to implement and go to market. Many of these submodules have been carried forward into the Coldfire line of processors.

The microcontrollers consist of a series of modules, connected by an internal bus:

• A fully static CPU core, capable of running at any clock speed from dead stop to maximum rated speed (25 or 33MHz).
• A CPU core designed to minimize transistors while maximizing performance.
• A high-speed clocked serial interface for debugging called background debug mode
  In-circuit emulator
  An in-circuit emulator is a hardware device used to debug the software of an embedded system. It was historically in the form of bond-out processor which has many internal signals brought out for the purpose of debugging...
  
   (BDM). The 683xx-series was the first to have a clocked serial interface to the CPU to perform debugging. Now, many CPUs use a standard serial test interface, usually JTAG
  JTAG
  Joint Test Action Group is the common name for what was later standardized as the IEEE 1149.1 Standard Test Access Port and Boundary-Scan Architecture. It was initially devised for testing printed circuit boards using boundary scan and is still widely used for this application.Today JTAG is also...
  
  , for this purpose.
• The SIM (System Integration Module), which eliminates much glue logic
  Glue logic
  In electronics, glue logic is the custom logic circuitry used to interface a number of off-the-shelf integrated circuits.This is often achieved using ordinary 7400- or 4000-series components. In more complex cases, programmable logic devices like a CPLD or FPGA might be used...
  
   by providing chip selects and address decoding. The SIM also provides a clock generator, watchdogs for various system operations, configuration of processor pins, a periodic timer, and an interrupt controller.

Other modules available on various processors in the 683xx family are:

• The Timing Processor Unit (TPU), which performs almost any timing related task: timers, counters, proportional pulse width control, pulse width measurement, pulse generation, stepper motor controllers, quadrature detection, etc. Freescale gives the development system and code
  Source code
  In computer science, source code is text written using the format and syntax of the programming language that it is being written in. Such a language is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source...
  
   away for free.
• An auxiliary RAM
  Random-access memory
  Random access memory is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time. Strictly speaking, modern types of DRAM are therefore not random access, as data is read in...
  
   doubles as a programmable microcontroller store for the TPU.
• Some early models have two conventional counter-timers.
• A general purpose timer (GPT) module provides pulse accumulators, capture/compare, and Pulse-width modulation
  Pulse-width modulation
  Pulse-width modulation , or pulse-duration modulation , is a commonly used technique for controlling power to inertial electrical devices, made practical by modern electronic power switches....
  
   capabilities.
• Some models have a network interface processor in the form of a communications processor module (CPM) and serial communications controllers (SCC) which can be interfaced to Ethernet
  Ethernet
  Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
  
   or HDLC busses.
• Most models have a queued serial module (QSM) which provides both synchronous Serial Peripheral Interface (SPI), and logic-level RS232 UART capabilities.

External links

• Freescale M683xx processors