What this 8051-based MCU brings to the board
The Maxim Integrated DS80C390-FNR+ is an 8-bit microcontroller built around the 8051 core, clocked at 40 MHz. It's a ROMless device — there's no internal program memory — so you pair it with external Flash or ROM via the external bus interface (EBI/EMI). The 4K x 8 internal RAM handles scratchpad and stack. This part is aimed at industrial control, automotive networking, and any application needing a proven 8051 architecture with CANbus on-chip.
Package and mounting
The 40 MHz clock is the maximum internal operating frequency. For a standard 8051 core, most instructions execute in 4 clocks.
Peripheral set for control and comms
32 general-purpose I/O pins are available. The supply range is 3.85 V to 5.5 V.
Package, temperature, and environment
Housed in a 64-LQFP (10x10 mm) surface-mount package, the DS80C390-FNR+ operates from -40°C to 85°C.
Lifecycle and compliance
The DS80C390-FNR+ is listed as Active in production. That means no last-time-buy clock is ticking, and you can plan for ongoing builds without worrying about a sudden EOL. It is RoHS3 compliant, so it meets the latest EU restriction requirements for lead and other substances.