Analog Devices Inc./Maxim Integrated DS80C320-MNL

Overview

DS80C320-MNL from Maxim Integrated is a high-speed, 80C32-compatible 8-bit microcontroller with 4-clock-per-machine-cycle architecture, 33MHz max crystal frequency, -40°C to +85°C industrial temperature range, and 40-pin PDIP package. It delivers ~2.5× average instruction speedup over standard 80C32 while maintaining full pin and instruction set compatibility, enabling drop-in performance upgrades in legacy 5V embedded control systems.

For engineers reviewing the DS80C320-MNL datasheet, DS80C320-MNL pinout, DS80C320-MNL application, or DS80C320-MNL equivalent, key selection considerations include its dual hardware serial ports, programmable MOVX memory access stretch (2–9 cycles), dual data pointer for accelerated block moves, power-fail reset/interrupt, and watchdog timer - all within a ruggedized industrial-grade 40-pin DIP footprint.

Technical Context

The DS80C320-MNL implements a redesigned 8051 core eliminating wasted clock and memory cycles, executing most instructions in 4 oscillator clocks versus 12 in legacy 80C32. Its dual SFR-mapped serial ports (UART0 on P3.0/P3.1, UART1 on P1.2/P1.3) operate independently with configurable baud rates using Timer 1 (both) or Timer 2 (UART0 only).

Memory interface uses multiplexed P0 (AD0–AD7) and P2 (A8–A15) with software-controllable MOVX timing via CKCON register (SFR 8Eh, bits M2–M0), enabling seamless interfacing to both fast SRAM and slow peripherals like LCD controllers without external glue logic.

Key Specifications

Pinout & Package

DS80C320-MNL is housed in a 40-pin plastic dual in-line package (PDIP) with 0.6-inch body width and 0.1-inch pin pitch, compatible with standard through-hole PCB assembly and socketing for prototyping and industrial maintenance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8051-compatible microcontroller applications.

Compared with DS80C323-MND and AT89C51RD2-SLSUM, the DS80C320-MNL uniquely combines industrial temperature range, 33MHz speed, dual UARTs, MOVX timing control, and power-fail safety features in a legacy-compatible 40-pin DIP - making it the sole option for ruggedized drop-in upgrades requiring full feature parity.

Availability

DS80C320-MNL is available at Aetrix Electronics and suitable for industrial PLCs, smart energy meters, legacy equipment retrofits, and medical infusion pumps requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for DS80C320-MNL includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and embedded solutions for industrial, automotive, and communications markets.

The DS80C320-MNL belongs to Maxim's high-speed 8051 microcontroller family, designed specifically to extend the life of legacy 80C32-based systems by delivering 2.5× performance in pin-compatible packages without requiring firmware or layout changes.

FAQ

What is the maximum crystal frequency supported by the DS80C320-MNL?

The DS80C320-MNL supports a maximum crystal frequency of 33MHz, enabling an apparent execution speed of approximately 82.5MHz due to its 4-clock-per-machine-cycle architecture. This is confirmed in the Ordering Information table and Detailed Description section of the official Maxim datasheet, where DS80C320-MNL is explicitly listed with "MAX CLOCK SPEED (MHz): 33" and "TEMP RANGE: -40°C to +85°C". The device maintains full 80C32 instruction set compatibility at this speed.

Does the DS80C320-MNL require external pull-up resistors on Port 0?

Yes, the DS80C320-MNL requires external pull-up resistors on Port 0 (P0.0–P0.7) when used as a bidirectional data bus during MOVX operations. As stated in the PIN DESCRIPTION section, Port 0 has "no true port latch" and cannot drive high actively; its reset state is high due to weak internal pull-ups insufficient for bus driving. External 4.7kΩ pull-ups are standard practice to ensure reliable data bus signaling during external RAM or peripheral access - a requirement inherited from the original 80C32 architecture.

How does the dual data pointer (DPTR0/DPTR1) improve performance in the DS80C320-MNL?

The dual data pointer in the DS80C320-MNL reduces 64-byte RAM-to-RAM block moves from 1869 to 1097 machine cycles - a 42% reduction - by eliminating software overhead for saving and restoring address registers. As documented in the Dual Data Pointer section, DPTR0 (SFR 82h/83h) and DPTR1 (SFR 84h/85h) are selected via the DPS bit (SFR 86h, LSB), allowing instantaneous switching between source and destination addresses. This accelerates firmware tasks like EEPROM parameter backup and buffer management without increasing code size or interrupt latency.

Can the DS80C320-MNL operate with a 3.3V supply?

No, the DS80C320-MNL cannot operate with a 3.3V supply. Its absolute maximum ratings specify a minimum VCC of 4.25V and maximum of 5.5V, as clearly stated in the Detailed Description: "The DS80C320 operating voltage ranges from 4.25V to 5.5V". For 3.3V operation, the pin-compatible DS80C323 variant (e.g., DS80C323-MND) must be used instead, which supports 2.7V–5.5V but is limited to 18MHz maximum clock speed.

What is the function of the EA pin on the DS80C320-MNL, and how should it be connected?

The EA (External Access) pin on the DS80C320-MNL must be connected to ground (LOW) for proper operation, as explicitly required in the PIN DESCRIPTION section. Since the DS80C320-MNL contains no on-chip ROM, EA=LOW enables external program memory access via P0 and P2 address/data buses. Leaving EA floating or tying it HIGH would disable external code fetch and cause undefined behavior - a critical hardware design requirement confirmed across all Maxim documentation for this part.