STMicroelectronics SERC816

Overview

SERC816 from SERCON is a single-chip SERCOS interface controller IC 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 optical fiber or RS-485 ring/bus topologies, and delivers up to 16 Mbaud with internal clock recovery - deployed in CNC drive master/slave nodes.

For engineers reviewing the SERC816 datasheet, SERC816 pinout, SERC816 application, or SERC816 equivalent, key selection criteria include SERCOS cycle timing compliance (62.5 µs–65 ms), dual-port RAM buffering mode (single/double/DMA), serial interface repeater capability, watchdog supervision of sync signals, and compatibility with SERCON410B legacy systems.

Technical Context

The SERC816 implements a deterministic, cycle-synchronized communication engine with programmable CYC_CLK input and CON_CLK/DIV_CLK timing outputs. Its telegram processor handles automatic synchronous/data telegram transmission and service channel scheduling across fixed-duration cycles without CPU intervention.

It embeds a fully integrated serial physical layer supporting both optical fiber (with transmitter power modulation and L_ERRN line error detection) and RS-485 busses, including an internal repeater for ring topologies and independent TxD/RxD clock regeneration at up to 16 Mbaud - all synchronized to MCLK (12–64 MHz) and SCLK (up to 64 MHz).

Key Specifications

Pinout & Package

Package: 100-pin Plastic Quad Flat Pack (PQFP100), lead-free compatible, 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 adds ring repeater, 4× higher baud rate, and richer timing outputs - enabling larger, more deterministic motion networks. Versus SERCOS III ICs, it retains SERCOS I compatibility but lacks Ethernet integration - making it optimal for cost-sensitive, field-proven industrial drives.

Availability

SERC816 is available at Aetrix Electronics and suitable for industrial servo drives, CNC controllers, test equipment, and motion control modules requiring stable component supply across extended product lifecycles.

Supply support for SERC816 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 company specializing in industrial communication interface controllers, founded in the early 1990s and acquired by Infineon Technologies in 2005.

The SERCOS interface controller product line - including SERC816 - was designed specifically for deterministic real-time motion control in factory automation, targeting SERCOS I compliance, optical noise immunity, and minimal host MCU overhead.

FAQ

What bus interface standards does SERC816 support?

SERC816 supports both Intel-style (RDN/WRN active-low strobes) and Motorola-style (RDN as data strobe, WRN as R/W select) 8/16-bit parallel bus protocols. Bus mode is selected via BUSMODE[1:0] pins at reset, and byte ordering (low/high byte first) is controlled by BYTEDIR. No external glue logic is required for either standard.

How does SERC816 handle SERCOS ring topology without external repeaters?

SERC816 integrates a hardware repeater function activated automatically in ring mode. When TM0/TM1 pins are set to enable repeater at reset, the device regenerates incoming serial data and forwards it to the next node - eliminating need for discrete repeater ICs or FPGA logic in multi-slave optical rings.

Can SERC816 operate with RS-485 instead of optical fiber?

Yes - SERC816 supports RS-485 bus and ring topologies via its TxD/RxD pins driving external RS-485 transceivers. The same telegram processor, dual-port RAM, and timing engine are used; only the physical layer changes. Electrical characteristics (e.g., L_ERRN assertion on signal distortion) remain fully functional.

Is SERC816 pin-compatible with SERCON410B?

No - SERC816 uses a 100-pin PQFP package while SERCON410B uses a 40-pin DIP. However, SERC816 offers SERCON410B compatibility mode (SBAUD16 = 1), which aligns register maps and basic timing behavior - enabling firmware reuse and simplified migration, though PCB layout requires redesign.