NXP Semiconductors MC68MH360ZP25VL

Overview

MC68MH360ZP25VL from Freescale Semiconductor is a QUICC (Quad Integrated Communications Controller) microcontroller unit integrating a 25 MHz ColdFire core, dual-channel TDM serial interface, and QMC (QUICC Multichannel Controller) for ISDN BRI/PRI, E1/T1, and HDLC/transparent channel aggregation. It supports up to 64 time slots per direction, 4 SCCs with independent protocol handling, and MSC (Multi-Subchannel) microcode for bit-level subchanneling. Used in telecom access gateways and ISDN terminal adapters.

For engineers reviewing the MC68MH360ZP25VL datasheet, MC68MH360ZP25VL pinout, MC68MH360ZP25VL application, or MC68MH360ZP25VL equivalent, key selection criteria include TDM bus timing compliance, QMC buffer descriptor RAM layout, SCC interrupt latency under multi-channel load, and MSC microcode support for fractional subchannel allocation in legacy ISDN infrastructure.

Technical Context

The MC68MH360ZP25VL implements a CPM (Communications Processor Module) architecture with dedicated RISC microcode engines for each of its four SCCs (Serial Communication Controllers), enabling concurrent HDLC, transparent, and ISDN LAPD frame processing without CPU intervention. Its QMC subsystem manages time-slot assignment tables (TSAT), dual-ported RAM pointers, and global overrun/underrun exception handling across all channels.

It operates with a 25 MHz internal core clock and supports external TDM bus synchronization at 2.048 MHz (E1) or 1.544 MHz (T1), with programmable SI (Serial Interface) routing logic that enables flexible mapping between SCCs and physical time slots. The device uses a 256-pin PQFP package and requires external boot ROM and DRAM for full QMC operation.

Key Specifications

Pinout & Package

MC68MH360ZP25VL is housed in a 256-pin Plastic Quad Flat Package (PQFP) with 0.5 mm pitch, thermal pad exposed on underside for heatsinking in telecom line-card applications. Pinout conforms to Freescale's MC68MH360 family layout, with dedicated TDM bus pins (TCLK, TFCLK, TRCLK, TSCLK), SCC I/O groups (SCC1–SCC4), and CPM control signals (SI, SICR, GSMR).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multichannel TDM controller applications.

Compared with MPC860MHZP25D4 and MC68360ZP25VL, the MC68MH360ZP25VL uniquely balances deep TDM integration (QMC + MSC) with ColdFire real-time determinism-making it optimal for ISDN-centric edge devices requiring field-upgradable channel mapping and bit-granular telemetry.

Availability

MC68MH360ZP25VL is available at Aetrix Electronics and suitable for ISDN terminal adapters, E1 access gateways, and PRI channel banks requiring stable component supply through extended industrial lifecycles.

Supply support for MC68MH360ZP25VL 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

Freescale Semiconductor (now part of NXP Semiconductors) was a leading designer of embedded processors and communications ICs, specializing in automotive, industrial, and networking solutions before its 2015 acquisition.

The MC68MH360ZP25VL belongs to the QUICC family, engineered specifically for telecom infrastructure edge devices requiring deterministic TDM channel handling, ISDN protocol offload, and low-latency CPM-based communications processing.

FAQ

What is the maximum number of time slots supported by the QMC in MC68MH360ZP25VL?

The QMC in MC68MH360ZP25VL supports up to 64 receive and 64 transmit time slots, configurable via TSATRx and TSATTx tables. This capacity enables full PRI (30B+D) or dual-BRI aggregation with headroom for future expansion. Each slot maps to an individual SCC channel or MSC subchannel, and the limit is enforced by the 6-bit TSAT index field in the QMC memory map.

Does MC68MH360ZP25VL support both E1 and T1 framing natively?

Yes, MC68MH360ZP25VL natively supports both E1 (2.048 MHz) and T1 (1.544 MHz) framing through its programmable TDM interface. The SI clock generator and frame sync logic adapt automatically based on SICR register settings, and the QMC's time-slot assignment engine maintains alignment regardless of frame structure-critical for mixed-mode carrier deployments.

How does the Multi-Subchannel (MSC) microcode in MC68MH360ZP25VL improve bandwidth efficiency?

The MSC microcode in MC68MH360ZP25VL allows a single 64 kbps time slot to be partitioned into up to four independent 2-bit subchannels, each with dedicated buffer descriptors and interrupt masking. This eliminates idle bandwidth in telemetry applications where sensors transmit only status bits, increasing effective channel density by 4× within the same E1/T1 pipe without protocol overhead.

What external memory is required for full QMC operation in MC68MH360ZP25VL?

Full QMC operation in MC68MH360ZP25VL requires external 2 MB DRAM for data buffers and 512 KB SRAM for parameter RAM and TSAT storage. The on-chip 8 KB dual-ported RAM serves only as CPM working memory; external memory must be connected via the 32-bit data/24-bit address bus with wait-state control configured in BRx/ORx registers.

Can MC68MH360ZP25VL replace MC68360ZP25VL without hardware changes?

MC68MH360ZP25VL is pin-compatible with MC68360ZP25VL and shares identical power, clock, and memory interface requirements. However, firmware must be updated to leverage QMC-specific registers (e.g., TSAT, MCBASE) and MSC microcode-no PCB changes are needed, but bootloader and CPM initialization code require revision to enable advanced QMC features.