STMicroelectronics SERC816/TR

Overview

SERC816/TR from SERCON is a single-chip SERCOS interface controller IC designed for real-time industrial motion control systems. It implements full SERCOS protocol hardware acceleration, supports 8/16-bit Intel/Motorola bus interfaces, integrates 2048 × 16-bit dual-port RAM, enables 16 Mbaud optical fiber or RS-485 ring/buss communication, and provides internal clock recovery and repeater functionality - deployed in CNC drive master/slave nodes.

For engineers reviewing the SERC816/TR datasheet, SERC816/TR pinout, SERC816/TR application, or SERC816/TR equivalent, key selection considerations include SERCOS cycle timing compliance (62.5 µs–65 ms), dual-port RAM buffering mode (single/double buffer or DMA), optical transmitter power modulation control, and SERCON410B compatibility mode via SBAUD16 pin.

Technical Context

The SERC816/TR implements a deterministic, cycle-synchronized SERCOS communication stack in hardware: telegram processing logic autonomously handles synchronous and data telegrams per cycle, with automatic service channel transmission across multiple cycles. Its serial interface includes integrated clock recovery, line error detection (L_ERRN), receive active signaling (RECACTN), and programmable transmit clock (TxC) and receive clock (RxC) generation.

Timing control is fully configurable: CYC_CLK synchronizes the communication cycle (programmable polarity), CON_CLK and DIV_CLK provide programmable control pulses within or across cycles, and TM0/TM1 pins configure test modes and repeater enable at reset. The device supports both master and slave roles in fiber-optic ring or RS-485 bus topologies without external repeater ICs.

Key Specifications

Pinout & Package

Package: PQFP100 (Plastic Quad Flat Pack, 100-pin, 0.65 mm pitch), JEDEC MS-026AC compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SERCOS interface controller applications.

Compared with SERCON410B, SERC816/TR delivers 2× data rate and eliminates external repeater dependency; versus TLE987x, it provides deterministic sub-microsecond telegram latency without MCU scheduling overhead - making it optimal for hard real-time motion control nodes.

Availability

SERC816/TR is available at Aetrix Electronics and suitable for CNC machine tool drives, industrial servo amplifiers, automated test equipment controllers, and modular PLC backplanes requiring stable component supply and long-term industrial lifecycle support.

Supply support for SERC816/TR 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

SERCON is a German semiconductor design house specializing in industrial real-time communication controllers, founded in the early 1990s to address deterministic fieldbus requirements in motion control.

The SERCON816 product line was developed specifically to implement SERCOS I protocol in hardware, enabling plug-and-play interoperability between CNC controllers and digital servo drives in factory automation environments.

FAQ

What bus interface standards does SERC816/TR support?

SERC816/TR supports both Intel-style (RDN=active-low read, WRN=active-low write) and Motorola-style (RDN=data strobe, WRN=read/write select) 8/16-bit parallel bus protocols. BUSMODE0/1 and BUSWIDTH pins configure interface mode at power-up; no firmware reconfiguration is needed after initialization.

How does SERC816/TR handle SERCOS cycle synchronization?

SERC816/TR uses the CYC_CLK input pin to lock its internal timing engine to an external master clock. The polarity and edge sensitivity of CYC_CLK are programmable via control registers. Once synchronized, CON_CLK and DIV_CLK outputs provide precisely timed control pulses aligned to the SERCOS cycle boundary for peripheral coordination.

Can SERC816/TR operate without optical fiber?

Yes - SERC816/TR natively supports RS-485 electrical layer via the same TxD/RxD pins. It can be configured for RS-485 bus or ring topology using external drivers (e.g., SN75176), eliminating need for optical transceivers in cost-sensitive or short-distance applications while retaining full SERCOS protocol compliance.

What is the role of the dual-port RAM in SERC816/TR operation?

The 2048 × 16-bit dual-port RAM stores SERCOS telegram headers, data containers, service channels, and end markers. It allows concurrent access: the SERCOS engine writes received telegrams and reads transmit buffers while the host CPU reads status or loads new commands - enabling zero-copy, interrupt-driven communication without CPU polling.