Analog Devices Inc./Maxim Integrated DS80C320-FCG

Overview

DS80C320-FCG from Maxim Integrated is a high-speed, 80C32-compatible 8-bit microcontroller with 4-clock-per-machine-cycle architecture, 256 bytes of on-chip RAM, three 16-bit timer/counters, and dual full-duplex hardware serial ports. It operates at up to 33 MHz (82.5 MHz effective throughput), supports 64 kB external program and data memory addressing, and delivers 2.5× average instruction speedup over standard 8051 cores - used in industrial control panels requiring deterministic real-time I/O response.

For engineers reviewing the DS80C320-FCG datasheet, DS80C320-FCG pinout, DS80C320-FCG application, or DS80C320-FCG equivalent, key selection criteria include its 40-pin DIP package compatibility with legacy 80C32 designs, programmable MOVX memory access stretch (2–9 cycles), dual data pointer acceleration for block transfers, power-fail reset/interrupt, and watchdog timer - all critical for upgrade paths in field-deployed 5V embedded systems.

Technical Context

The DS80C320-FCG implements a redesigned 8051 core eliminating dummy clock 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, while timer resources (T0/T1/T2) default to 12-clock mode for backward timing compatibility but support 4-clock operation via CKCON register bits.

Memory interface uses Port 0 (AD0–AD7) as multiplexed address/data bus with ALE strobe, Port 2 (A8–A15) as high-byte address output, and EA grounded for external code execution. The Stretch MOVX feature - controlled by CKCON.2–0 - dynamically adjusts RD/WR strobe width from 80 ns to 1120 ns at 25 MHz, enabling direct interfacing with diverse peripherals including slow LCD controllers and fast SRAM without glue logic.

Key Specifications

Pinout & Package

DS80C320-FCG is housed in a 40-pin plastic dual in-line package (PDIP) with 0.6-inch body width, through-hole mounting, and industry-standard 0.1-inch pin pitch. Pin functions align with 80C32 compatibility while adding new capabilities on Port 1 and dedicated control signals.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with DS80C320-MCL+, the DS80C320-FCG shares identical electrical specs and timing but carries legacy RoHS exemption coding; compared with DS80C323-QCD+, it offers higher performance and DIP compatibility but lacks wide-voltage support - making DS80C320-FCG optimal for cost-sensitive, space-constrained 5 V industrial upgrades.

Availability

DS80C320-FCG is available at Aetrix Electronics and suitable for industrial control panels, legacy 8051 system upgrades, energy meter communication hubs, and building HVAC controllers requiring stable component supply and long-term obsolescence management.

Supply support for DS80C320-FCG 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 semiconductor company specializing in high-performance analog, mixed-signal, and embedded processing solutions for industrial, communications, and computing markets.

The DS80C320-FCG belongs to Maxim's high-speed 8051 microcontroller family, engineered to deliver 2.5× performance uplift in legacy 5 V embedded systems while maintaining full software and pin compatibility with standard 80C32 designs.

FAQ

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

The DS80C320-FCG supports a maximum crystal frequency of 33 MHz, enabling an effective instruction throughput of approximately 82.5 MHz due to its 4-clock-per-machine-cycle architecture. This specification is confirmed in the Ordering Information table and Electrical Characteristics section of the official Maxim datasheet. Operation above 33 MHz is not guaranteed and may result in timing violations or unstable behavior. DS80C320-FCG must be operated within this limit for reliable function across its rated temperature range.

Is DS80C320-FCG pin-compatible with standard 80C32 microcontrollers?

Yes, DS80C320-FCG is fully pin-compatible with the industry-standard 80C32 in the 40-pin DIP package, including identical signal assignments for VCC, GND, RST, XTAL1/XTAL2, P0–P3, PSEN, ALE, and EA. All control and I/O signals retain their original 80C32 roles, allowing direct PCB-level replacement. DS80C320-FCG retains backward compatibility while adding new functions on Port 1 pins (e.g., RXD1/TXD1) that remain tri-stated unless enabled via SFR configuration.

Does DS80C320-FCG include on-chip flash or ROM memory?

No, DS80C320-FCG does not contain any on-chip program memory (ROM or flash). It is a ROMless variant requiring external program memory accessed via the multiplexed P0 address/data bus and P2 address lines. The device includes only 256 bytes of on-chip scratchpad RAM. DS80C320-FCG must have EA pin tied to GND to enable external code execution - a design requirement explicitly stated in the Pin Description and Electrical Specifications sections of the datasheet.

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

The dual data pointer in DS80C320-FCG reduces memory block transfer overhead by eliminating the need to save and restore address registers during moves. With DPS bit (SFR 86h) toggling between DPTR0 (82h/83h) and DPTR1 (84h/85h), a 64-byte RAM-to-RAM copy executes in 1097 machine cycles versus 1869 cycles using a single DPTR - a 41% reduction. DS80C320-FCG leverages this feature for accelerated EEPROM buffering, display frame updates, and protocol packet assembly without additional CPU intervention.

What is the function of the CKCON register in DS80C320-FCG?

The CKCON register (SFR address 8Eh) in DS80C320-FCG controls two critical timing features: MOVX memory access stretch (bits 2–0) and per-timer clock division (bits 3–5). Setting CKCON.2–0 selects RD/WR strobe width from 2 to 9 machine cycles, enabling interface flexibility with slow peripherals. Bits CKCON.3–5 independently configure T0/T1/T2 to run at either 4-clock (high-speed) or 12-clock (legacy-compatible) mode - preserving timing-critical firmware while allowing selective acceleration. DS80C320-FCG defaults to CKCON = 0x02 after reset, enabling 3-cycle MOVX and 12-clock timers.