Analog Devices Inc./Maxim Integrated DS80C320-QCL

Overview

DS80C320-QCL from Maxim Integrated is a high-speed, 80C32-compatible 8-bit microcontroller featuring a 4-clock-per-machine-cycle core, 33MHz maximum crystal frequency, 256 bytes of on-chip RAM, three 16-bit timer/counters, and dual full-duplex hardware serial ports. It operates from 4.25V to 5.5V and targets legacy 8051 system upgrades requiring deterministic real-time control in industrial instrumentation and embedded communications.

For engineers reviewing the DS80C320-QCL datasheet, DS80C320-QCL pinout, DS80C320-QCL application, or DS80C320-QCL equivalent, key selection considerations include its 4-clock architecture versus standard 8051 timing, 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 44-pin PLCC package rated for 0°C to +70°C operation.

Technical Context

The DS80C320-QCL implements a redesigned 8051-compatible core eliminating wasted clock and memory cycles, delivering 2.5× average instruction speed improvement over the original 80C32 at identical crystal frequencies. Its machine cycle executes in 4 oscillator clocks instead of 12, enabling single-cycle instructions in 121ns at 33MHz.

It retains full 80C32 pin and instruction set compatibility while adding new peripherals accessed via non-overlapping SFRs: a second UART (P1.2/P1.3), seven additional interrupt sources, early-warning power-fail interrupt, and programmable watchdog timer. Timer/counter operation defaults to 12-clock mode on reset for backward timing compatibility but supports 4-clock mode via CKCON register bits.

Key Specifications

Pinout & Package

DS80C320-QCL is housed in a 44-pin Plastic Leaded Chip Carrier (PLCC) package with J-lead geometry, designed for surface-mount assembly and socketed prototyping. Pin 1 is located at the index corner adjacent to the notch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS80C320-MCL, DS80C320-QCL provides denser I/O routing and full A8–A15 address lines in surface-mount form; compared with DS80C320-QNL, it trades extended temperature capability for lower cost and qualification time in commercial-grade applications.

Availability

DS80C320-QCL is available at Aetrix Electronics and suitable for industrial PLC I/O modules, legacy 8051 system upgrades, embedded communications gateways, and test equipment controllers requiring stable component supply and long-term manufacturing continuity.

Supply support for DS80C320-QCL 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 precision analog, mixed-signal, and high-reliability microcontrollers for industrial, medical, and communications applications.

The DS80C320-QCL belongs to Maxim's high-speed 8051-compatible microcontroller product line, engineered to deliver deterministic real-time performance and seamless migration paths for designers maintaining legacy 80C32-based systems.

FAQ

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

The DS80C320-QCL supports a maximum crystal frequency of 33MHz, enabling single-cycle instruction execution in 121ns. This specification is confirmed in the Ordering Information table and Detailed Description section of the official datasheet. The device achieves an apparent execution speed of approximately 82.5MHz due to its 4-clock-per-machine-cycle architecture. Operation above 33MHz violates absolute maximum ratings and may cause timing violations or functional failure in DS80C320-QCL.

Does the DS80C320-QCL include on-chip flash or ROM memory?

No, the DS80C320-QCL does not include on-chip program memory. It contains only 256 bytes of on-chip scratchpad RAM and requires external program memory accessed via the multiplexed P0 address/data bus and P2 upper address lines. This matches the architecture of the original 80C32 and is explicitly stated in the MEMORY ACCESS section of the datasheet. The EA pin must be tied low to enable external ROM fetches in DS80C320-QCL.

How does the dual data pointer in the DS80C320-QCL improve memory block transfers?

The DS80C320-QCL implements two independent 16-bit data pointers (DPTR0 at 82h/83h and DPTR1 at 84h/85h), selected via the DPS bit at SFR 86h. This eliminates software overhead for saving and restoring address registers during block moves. As verified in the DUAL DATA POINTER section, a 64-byte transfer executes in 1097 machine cycles instead of 1869 - a 41% reduction - directly measurable in DS80C320-QCL firmware benchmarks at 25MHz.

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

No, the DS80C320-QCL is specified for 4.25V to 5.5V operation only. Its electrical characteristics, including noise margins and timing parameters, are characterized exclusively within this range. For 3.3V operation, designers should select the pin-compatible DS80C323 variant (e.g., DS80C323-QCD), which supports 2.7V to 5.5V and shares the same 44-pin PLCC footprint and peripheral set as DS80C320-QCL.

What is the function of the N.C. pins on the DS80C320-QCL PLCC package?

The DS80C320-QCL datasheet identifies Pins 12, 34, 6, 28, and 39 as N.C. (No Connection), reserved for future family expansion. These pins must remain unconnected in all DS80C320-QCL applications - soldering or routing to them may cause undefined behavior or damage. This requirement is explicitly documented in the PIN DESCRIPTION section and applies strictly to DS80C320-QCL; other variants in the family use these pins differently.