DS89C420-MNL Maxim Integrated Products, DS89C420-MNL Datasheet - Page 14

• Manufacturer Part Number: DS89C420-MNL
• Description: IC MCU ULTRA 33MHZ HP 40-DIP
• Manufacturer: Maxim Integrated Products
• Series: 89Cr

Specifications of DS89C420-MNL

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 33MHz
• Connectivity: EBI/EMI, SIO, UART/USART
• Peripherals: Power-Fail Reset, WDT
• Number Of I /o: 32
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -

Figure 5. Block Diagram
DETAILED DESCRIPTION
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, brownout 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.
Dallas Semiconductor
Control &
Sequencer
Watchdog Timer
Power Manager
Decoder
DS89C420
IR
&
Internal Control Bus
Serial I/O
Internal
Registers
Clock &
Timer /
Counters
Reset
14 of 47
Interrupt
CPU
1Kx 8
RAM
Memory
Control
DPTR1
16K x 8
SFRs
DPTR
Loader
Flash
ROM
SP
P0 P1 P2 P3
AR Inc
I/O Ports
Address Bus
PC
AR