High-Speed Microcontroller

The DS89C420 Ultra High-Speed Microcontroller is completely 8051-compatible and achieves peak processing speeds of one machine instruction per clock cycle, or 50 MIPS (million instructions per second) at a maximum clock speed of 50 MHz. The device features 16 kilobytes of Flash memory that allows programming in any of three modes: in-system, in-application or standard parallel programming. These enhancements result from a new redesign of the 8051 processing core and advanced memory address/access methods. The device remains 100% pin- and instruction-set compatible with existing 8051-based systems.

The device's memory architecture contributes to faster processing and extends the concept of field programmability. Internal memory management logic enables application software to dynamically configure on-chip memory blocks by executing user software in one block while reprogramming the other. When that block is reprogrammed, software can switch the blocks so that the other can be erased and reprogrammed. The Flash boot loader supports in-system programming through the serial port, opening the entire Flash memory to an external program source. The microcontroller also supports standard Flash or EPROM programmers.

Software written for existing 8051-based systems works with the new device, with the exception of critical timing routines. The microcontroller provides a stretch cycle feature and page or non-page memory interface modes to enable communication with slower external memory and peripherals.

The microcontroller features two data pointers that can be used to move blocks of data both forwards and backwards. Other resources include 13 interrupt sources with five priority levels instead of three, three 16-bit timer/counters and a watchdog timer. An internal clock divider circuit enables Power Management Mode, where the device selects a processing speed based on software input and maintains all processes at lower power states without shutting down. A clock multiplier is included to allow full-speed operation from lower speed, more readily available crystals.

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