© 2000 Scenix Semiconductor, Inc. All rights reserved. - 4 - www.scenix.com SX48BD/SX52BD/SX52BD75/SX52BD100 1.3 Architecture The  SX  devices  use  a  modified  Harvard  architecture. This architecture uses two separate memories with sepa- rate  address  buses,  one  for  the  program  and  one  for data, while allowing transfer of data from program mem- ory  to  SRAM.  This  ability  allows  accessing  data  tables from  program  memory.  The  advantage  of  this  architec- ture is that instruction fetch and memory transfers can be overlapped with a multi-stage pipeline, which means the next  instruction  can  be  fetched  from  program  memory while the current instruction is being executed using data from the data memory. Scenix has developed a revolutionary RISC-based archi- tecture  and  memory  design  techniques  that  is  20  times faster than conventional MCUs, deterministic, jitter free, and totally reprogramable. The  SX  family  implements  a  four-stage  pipeline  (fetch, decode, execute, and write back), which results in execu- tion  of  one  instruction  per  clock  cycle.  At the maximum operating  frequency  of  100  MHz,  instructions  are  exe- cuted at the rate of one per 10-ns clock cycle. 1.3.1  The Virtual Peripheral Concept Virtual Peripheral concept enables the “software system on a chip” approach. Virtual Peripheral, a software mod- ule that replaces a traditional hardware peripheral, takes advantage of the Scenix architecture’s high performance and deterministic nature to produce same results as the hardware peripheral with much greater flexibility. The speed and flexibility of the Scenix architecture com- plemented  with  the  availability  of  the  Virtual  Peripheral library, simultaneously address a wide range of engineer- ing  and  product  development  concerns.  They  decrease the  product  development  cycle  dramatically,  shortening time to production to as little as a few days. Scenix’s  time-saving  Virtual  Peripheral  library  gives  the system designers a choice of ready-made solutions, or a head start on developing their own peripherals. So, with Virtual  Peripheral  modules  handling  established  func- tions, design engineers can concentrate on adding value to other areas of the application. The concept of Virtual Peripheral combined with in-sys- tem re-programmability provides a powerful development platform  ideal  for  the  communications  industry  because of the numerous and rapidly evolving standards and pro- tocols. Overall, the concept of Virtual Peripheral provides bene- fits such as using a more simple device, reduced compo- nent  count,  fast  time  to  market,  increased  flexibility  in design,  customization  to  your  application  and  ultimately overall system cost reduction.        Some examples of Virtual Peripheral modules are: •    Communication interfaces such as I²C™, Microwire™ (µ-Wire), SPI, IrDA Stack, UART, and Modem func- tions •    Internet Connectivity protocols such as UDP, TCP/IP stack, HTTP, SMTP, POP3 •    Frequency generation and measurement •    PPM/PWM generation •    Delta/Sigma ADC •    DTMF generation/detection •    FFT/DFT based algorithms 1.3.2  The Communications Controller The combination of the Scenix hardware architecture and the Virtual Peripheral concept create a powerful, creative platform for the communications design communities. Its high  processing  power,  re-cofigurability,  cost-effective- ness, and overall design freedom give the designer the power to build products for the future with the confidence of knowing that they can keep up with innovation in stan- dards and other areas. 1.4 Programming and Debugging Support The  SX  devices  are  currently  supported  by  third  party tool vendors. On-chip in-system debug capabilities have been   added,   allowing   tools   to   provide   an   integrated development     environment     including     editor,     macro assembler, debugger, and programmer. Un-obtrusive in- system programming is provided through the OSC pins. For emulation purposes, there is no need for a bond-out chip, so the user does not have to worry about the poten- tial  variations  in  electrical  characteristics  of  a  bond-out chip  and  the  actual  chip  used  in  the  target  application. The user can test and revise the fully debugged code in the  actual  SX,  in  the  actual  application,  and  get  to  pro- duction much faster. 1.5 Applications Emerging  applications  and  advances  in  existing  ones require  higher  performance  while  maintaining  low  cost and fast time-to-production. The SX device provides solutions for many familiar appli- cations   such   as   process   controllers,   electronic   appli- ances/tools,     security/monitoring     systems,     consumer automotive,  sound  generation,  motor  control,  and  per- sonal communication devices. In addition, the device is suitable  for  applications  that  require  DSP-like  capabili- ties, such as closed-loop servo control (digital filters), dig- ital answering machines, voice notation, interactive toys, and magnetic-stripe readers. Furthermore,  the  growing  Virtual  Peripheral  library  fea- tures  new  components,  such  as  the  Internet  Protocol stack,  and  communication  interfaces,  that  allow  design engineers to embed Internet connectivity into all of their products at extremely low cost and very little effort. Scenix’s  complete  network  connectivity  protocol  stack implementation   (SX-Stack),   enables   single-chip   Web servers and E-mail appliances in embedded applications. The implementation includes the physical layer interface with the TCP/IP network connectivity protocols, enabling system  designers  to  produce  cost-effective  embedded Internet  devices  without  external  physical  access  or  a gateway PC. The hardware platform for SX-Stack is the SX52BD com- munications controller. The device allows implementation of  the  entire  TCP/IP  protocols,  physical  interface,  and other  relevant  high-speed  communication  interfaces  as Virtual Peripheral modules.