Datasheet

DS89C430/DS89C450 Ultra-High-Speed Flash Microcontrollers
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Figure 5. Functional Diagram
CONTROL
AND
SEQUENCER
INTERNAL
REGISTERS
DECODE
R
IR
INTERRUPT
CPU
SERIAL I/O
TIMER/
COUNTERS
1kB x 8
RAM
16kB/32kB
64kB x 8
FLASH
I/O PORTS
SFRs
DPTR
DPTR1
SP
PC
AR INC
AR
WATCHDOG TIMER
AND
POWER MANAGER
CLOCK
AND
RESET
MEMORY
CONTROL
ROM
LOADER
XTAL2
XTAL1
RST
P
SEN
E
A
ALE/PROG
P0 P1
P2 P3
ADDRESS BUS
INTERNAL CONTROL BUS
DETAILED DESCRIPTION
The DS89C430 and DS89C450 are pin compatible with all three packages of the standard 8051 and include
standard resources such as three timer/counters, serial port, and four 8-bit I/O ports. The three part numbers vary
only by the amount of internal flash memory (DS89C430 = 16kB, DS89C450 = 64kB), which can be in-system/in-
application programmed from a serial port using ROM-resident or user-defined loader software. For volume
deployments, the flash can also be loaded externally using standard commercially available parallel programmers.
Besides greater speed, the DS89C430/DS89C450 include 1kB of data RAM, a second full hardware serial port,
seven additional interrupts, two extra levels of interrupt priority, programmable watchdog timer, brownout monitor,
and power-fail reset. Dual data pointers (DPTRs) are included to speed up block data-memory moves with further
enhancements coming from 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 cycles for flexibility in
selecting external memory and peripherals.
A power management mode consumes significantly lower power by slowing the CPU execution rate from one clock
period per cycle to 1024 clock periods per cycle. A selectable switchback feature can automatically cancel this
mode to enable normal speed responses to interrupts.
For EMI-sensitive applications, the microcontroller can disable the ALE signal when the processor is not accessing
external memory.
Dallas Semiconductor
DS89C430/
DS89C450