Renesas IDT79R3041-20J

Overview

IDT79R3041-20J from Integrated Device Technology is a 32-bit MIPS RISC microprocessor with integrated instruction cache (2 kB), data cache (512 B), programmable bus interface supporting 8-/16-/32-bit memory sub-regions, on-chip 24-bit timer, and DMA arbiter - designed for cost-sensitive embedded systems such as laser printers and PDL-based imaging devices.

For engineers reviewing the IDT79R3041-20J datasheet, IDT79R3041-20J pinout, IDT79R3041-20J application, or IDT79R3041-20J equivalent, key selection considerations include its 20 MHz operation, 84-pin PLCC package, software compatibility with IDT79R3000A and RISController family, double-frequency clock input, and support for booting from 8-/16-/32-bit PROMs without external packing logic.

Technical Context

The IDT79R3041-20J implements the MIPS-I ISA with a five-stage pipeline and full binary compatibility with the IDT79R3000A CPU core. It integrates CP0 system control co-processor registers for cache configuration, bus timing control, port width mapping, and 24-bit timer management - all accessible via kernel-mode software.

Its bus interface unit supports multiplexed 32-bit address/data bus with ALE, Rd/Wr handshaking, burst and single-word reads, and a 4-deep write buffer to eliminate memory write stalls. The device uses physical-address caches (direct-mapped, no context-switch flush required) and operates in big- or little-endian mode configurable at reset or dynamically.

Key Specifications

Pinout & Package

Package: 84-pin Plastic Leaded Chip Carrier (PLCC), cavity-down, commercial temperature grade (0°C to +85°C).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RISC microprocessor applications.

Compared with IDT79R3051-20J and IDT79RV3041-20J, the IDT79R3041-20J offers the lowest system cost for fixed-function embedded applications where virtual memory and voltage translation are unnecessary - retaining full software compatibility and identical 84-pin PLCC footprint.

Availability

IDT79R3041-20J is available at Aetrix Electronics and suitable for laser printer controllers, PostScript interpreter systems, industrial HMI terminals, and field-upgradeable embedded controllers requiring stable component supply across extended production lifecycles.

Supply support for IDT79R3041-20J 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

Integrated Device Technology, Inc. (IDT) was a fabless semiconductor company specializing in high-performance timing, memory interface, and embedded processor solutions before its acquisition by Renesas Electronics in 2019.

The IDT79R3041-20J belongs to the RISController™ family - a series of cost-optimized, highly integrated MIPS RISC microprocessors targeting low-cost embedded systems such as imaging devices, industrial controllers, and communications peripherals.

FAQ

What is the maximum operating frequency of the IDT79R3041-20J?

The IDT79R3041-20J is rated for 20 MHz core operation, achieved using a 40 MHz double-frequency clock input (ClkIn). Its performance is specified at 20 MIPS when executing from on-chip instruction cache. The "-20J" suffix explicitly denotes the 20 MHz speed grade and 84-pin PLCC package. This speed grade is validated across the commercial temperature range (0°C to +85°C) with appropriate thermal management.

Does the IDT79R3041-20J support booting from an 8-bit PROM?

Yes, the IDT79R3041-20J supports booting directly from 8-bit, 16-bit, or 32-bit wide PROMs without external data packing logic. This capability is enabled by its programmable port width control register in CP0, which allows the kernel to define memory sub-region widths. The device performs on-chip data unpacking during boot fetch, ensuring full software transparency across different PROM configurations.

Is the IDT79R3041-20J pin-compatible with other RISController family members?

Yes, the IDT79R3041-20J is superset pin-compatible with the IDT79R3000A and shares the same 84-pin PLCC footprint with IDT79R3051-20J and IDT79RV3041-20J. Pin compatibility includes identical A/D bus, control signal, interrupt, and clock pin assignments. However, some higher-end variants (e.g., R3051) expose additional TLB-related pins as NC on the IDT79R3041-20J.

What type of cache architecture does the IDT79R3041-20J implement?

The IDT79R3041-20J implements two separate direct-mapped physical-address caches: a 2 kB instruction cache with 16-byte line size and a 512 B write-through data cache with 4-byte line size. Both caches use physical tags and do not require flushing on context switch, simplifying real-time OS implementation. Cache behavior is controlled via CP0 configuration registers.

Does the IDT79R3041-20J include a memory management unit (MMU)?

No, the IDT79R3041-20J does not include a memory management unit or TLB. It implements the base version of the RISController architecture with fixed virtual-to-physical address mapping (kseg0/kseg1/kuseg), supporting kernel/user mode distinction via address decoding but without page-level protection or software-managed virtual memory. For MMU functionality, IDT79R3051-20J or IDT79R3081-20J must be selected.