Serial Communications Controller Cuts Power, Boosts Performance

With operating voltage reduced from 5 V to 3.3 V, the Z8523L enhanced serial communications controller (ESCC) serves a variety of computing applications requiring increased performance and lower power consumption. The device builds on the company’s discrete SCC and also features performance improvements that allow applications including computer peripherals, networking equipment and routers to experience faster data rates and increased processor bandwidth. Before developing the 3.3-V ESCC, it was necessary to add a regulator to achieve lower voltage with the original 5-V version. The Z8523L has deeper FIFOs and other features that significantly reduce the software overhead for each channel. This allows for more channels per system, faster data rates with more CPU bandwidth, and overall lower CPU costs. The ESCC can support multiple channels and multiple protocols that easily interface to 8/16-bit addressable non-multiplexed address/data buses. The ESCC can be configured to satisfy a wide variety of serial communications applications. On-chip features include baud rate generators, digital PLLs, and crystal oscillators to reduce external logic. Additional features may include optimized FIFOs to support high speed SDLC transfers using DMA controllers. The ESCC handles asynchronous formats, synchronous byte-oriented protocols, and synchronous bit-oriented protocols. The ESCC can generate and check CRC codes in any synchronous mode and can be programmed to check data integrity in various modes. The ESCC also has facilities for modem controls in both channels. In applications where these controls are not needed, the modem controls can be used for general-purpose I/O. The Zilog Z85230 enhanced SCC is in production. ZILOG INC., San Jose, CA. (408) 513-1500.