Flash Technology for Automobiles - Flexibility Integrated with High Performance

Why use flash technology rather than lower cost read-only-memory (ROM) in automotive applications? The key word is flexibility. Flash memory is engineered to allow car manufacturers to have the convenience of configuring a car's feature set and control algorithms at the last minute inside the factory. Thus, vehicles destined for different markets or with various customized options can still be assembled on the same production line as those vehicles with a standard feature set. The domino effect of this is significant to the entire design-supply-manufacturing chain; the benefit for MCU suppliers' is that they can reduce their custom parts inventory or completely eliminate it. Flash becomes invaluable during the development phase because the in-situ re-programmability of flash helps to shorten software development cycle times and eases final calibration of the engine.

Advantages of Integrated Flash Memory
Needless to say, there is an enormous drive towards cost reduction in the auto industry, which is being achieved through up-integration, miniaturization and mechatronics. On-chip flash is one component that enables improvements such as these, and has a number of other advantages.
  • Low car manufacturer exposure to commodity prices and delivery pressures that external flash products can incur.
  • Radiated interference to other devices such as car radios and mobile phones may be eliminated with on-chip flash because there are no high-speed external busses.
  • Dynamic production line programming. The use of two flash blocks permits on-the-fly calibration while code is executing (particularly useful when many data constants must be updated to fine tune the vehicle's performance while the car is being driven).
  • Simplifies embedded hardware erase and program algorithms in the calibration process.
  • On-chip flash beats the speed wall that external memory devices hit when clock rates exceed around 40MHz.
    An example of a highly integrated MCU with on-chip flash is the PowerPC instruction set architecture compatible - MPC565 from Freescale. It is manufactured with Motorola's 0.25u embedded nonvolatile memory wafer process, using high-density single transistor flash bit cells. Its logic core operates on a 2.6-V supply, while its peripherals maintain their compatibility with external voltages up to 5.0 V. The MPC565 has separate 32 byte on-chip page buffers to cache data and instruction streams fetched from memory. Combined with extended burst mode support, this results in a 200% performance boost over equivalent external flash memory systems.
    Disadvantages of External Flash Memory
  • 1M byte of on-chip flash is delivered in two 512Kbyte blocks, so you can run code from one block while programming the other.
  • You can program on the production line and/or in the field.
  • The code compression feature is designed to allow you to reduce the required program memory space by up to 45%.
  • The "censorship" feature helps you protect your data or software investment by locking your code into the device.
  • Ability to specify data retention times of 15 years and 1000 write/erase cycles
    When high performance must be coupled with high integration at lowest possible cost, MCUs with on-chip flash help deliver the goods!

    To learn more about the MPC565 and the benefits of flash, including extended burst mode support, on-chip security features, and code compression, visit the MPC565 Product Page