DS89C420MNL

The DS89C420MNL belongs to DS89C420 family, which offers the highest performance available in 8051-compatible microcontrollers. It features a redesigned processor core that executes every 8051 instruction (depending on the instruction type) up to 12 times faster than the original for the same crystal speed. Typical applications see a speed improve ment of 10 times using the same code and crystal. The DS89C420 offers a maximum crystal speed of 33MHz, achieving execution rates up to 33 million instructions per second (MIPS). The DS89C420 is pin compatible with all three packages of the standard 8051 and includes standard resources such as three timer/counters, four 8-bit I/O ports, and a serial port. It features 16kB of in-system programmable flash memory, which can be programmed in-system from an I/O port using a built-in program memory loader. It can also be loaded externally using standard commercially available programmers. Besides greater speed, the DS89C420 includes 1kB of data RAM, a second full-hardware serial port, seven additional interrupts, two more levels of interrupt priority, programmable watchdog timer, brown- out monitor, and power-fail reset. The device also provides dual data pointers (DPTRs) to speed up block-data memory moves. This feature is further enhanced with a new selectable automatic increment/decrement and toggle-select operation. The speed of MOVX data memory access can be adjusted by adding stretch values up to 10 machine cycle times for flexibility in selecting external memory and peripherals. A power management mode (PMM) significantly consumes less power by slowing the CPU execution rate from 1 clock period per cycle to 1024 clock periods per cycle. A selectable switchback feature can automatically cancel this mode to enable a normal speed response to interrupts. The EMI reduction feature disables the ALE signal when the processor is not accessing external memory.

The features of DS89C420 can be summarized as (1)80C52 compatible: 8051 pin and instruction-set compatible; four bidirectional I/O ports; three 16-bit timer counters; 256 bytes scratchpad RAM ; (2)on-chip memory; 16kB flash memory; in-system programmable through serial port; 1kB SRAM for MOVX ; (3)ROMSIZE feature: selects internal program memory size from ; (4)0 to 16k; allows access to entire external memory map; dynamically adjustable by software ; (5)high-speed architecture: 1 clock-per-machine cycle; DC to 33MHz operation; single-cycle instruction in 30ns; optional variable length MOVX to access fast/slow peripherals; dual data pointers with auto increment/decrement and toggle select; supports four paged modes ; (6)power management mode; programmable clock divider; automatic hardware and software exit ; (7)two full-duplex serial ports ; (8)programmable watchdog timer ; (9)13 interrupt sources (six external) ; (10)five levels of interrupt priority ; (11)power-fail reset ; (12)early warning power-fail interrupt.

The absolute maximum ratings of DS89C420 are (1)voltage range on any pin relative to ground: -0.3V to (VCC + 0.5V) ; (2)voltage range on VCC relative to ground: -0.3V to +6.0V ; (3)operating temperature range: -40°C to +85°C ; (4)storage temperature range: -55°C to +125°C ; (5)soldering temperature: see IPC/JEDEC J-STD-020A.( This is a stress rating only and functional operation of the device at these or other conditions beyond those indicated in the operations sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time can affect reliability.)