A systematic approach to software peripherals for embedded systems

ABSTRACT

The continued growth of microprocessors' performance and the need for better CPU utilization, has led to the introduction of the software peripherals' approach: By this term we refer to software modules that can successfully emulate peripherals that, until now, were traditionally implemented in hardware. Software implementations offer great flexibility in product design and in functional upgrades, while they have high contribution in the cost/performance ratio optimization. We focus on embedded applications, where the cost and the short time to market are the leading issues. In this paper, we study the hardware and software requirements for developing a generic microprocessor with support for software peripherals. Additionally, we present three software peripherals, a Universal Asynchronous Receiver Transmitter, a keypad controller and a dot matrix LCD controller, and we analyze their impact in CPU occupation. Finally, we explore the impact of using a software UART on system power dissipation.

REFERENCES

• 1: Manfred Schlett, Trends in Embedded-Microprocessor Design, Computer, v.31 n.8, p.44-49, August 1998 [doi>10.1109/2.707616]
• 2: J.Turley, "Evaluating Embedded Processors", Micro Design Resources, Sebastopole, Calif., 1997.
• 3: Dave Walsh, Reducing System Cost with Software Modems, IEEE Micro, v.17 n.4, p.37-43, July 1997 [doi>10.1109/40.612218]
• 4: Jennifer Eyre , Jeff Bier, DSP Processors Hit the Mainstream, Computer, v.31 n.8, p.51-59, August 1998 [doi>10.1109/2.707617]
• 5: J. R. Hauser , J. Wawrzynek, Garp: a MIPS processor with a reconfigurable coprocessor, Proceedings of the 5th IEEE Symposium on FPGA-Based Custom Computing Machines, p.12, April 16-18, 1997
• 6: Felice Balarin , Luciano Lavagno , Praveen Murthy , Alberto Sangiovanni-vincentelli, Scheduling for Embedded Real-Time Systems, IEEE Design & Test, v.15 n.1, p.71-82, January 1998 [doi>10.1109/54.655185]
• 7: Mark K. Gardner, Jane W.S. Liu, "Performance of Algorithms for Scheduling Real-Time Systems with Overrun and Overload", Prec. of 1 lth Euromicro Conf. on Real-Time Systems, June 1999 York, England.
• 8: Pai Chou , Gaetano Borriello, Interval scheduling: fine-grained code scheduling for embedded systems, Proceedings of the 32nd ACM/IEEE conference on Design automation, p.462-467, June 12-16, 1995, San Francisco, California, United States [doi>10.1145/217474.217571]
• 9: Vivek Tiwari , Sharad Malik , Andrew Wolfe, Power analysis of embedded software: a first step towards software power minimization, IEEE Transactions on Very Large Scale Integration (VLSI) Systems, v.2 n.4, p.437-445, Dec. 1994 [doi>10.1109/92.335012]
• 10: Jeffry T. Russell, Margarida F. Jacome, "So,ware Power Estimation & Optimization for High Performance 32bit Embedded Processors" Proceedings of ICCD '98, 5-7 October 1998 in Austin, Texas.
• 11: SH-DSP Microprocessor Overview. Hitachi Semiconductors Inc, 1998 Doc. Number PMH1DTB001D 1.
• 12: ARM Signal Processing Architecture Reference Manual. ARM Ltd, 1997. Doc. Number:. ARM IP0025B-07.
• 13: TfiCore Architecture Overview. Siemens Microelectronics, Inc., 1997. Order Number: M32T008.
• 14: Motorola Corporation software modem Home Page, http://www.mot.com/soflmodem
• 15: Ubicom (formerly Sceulx) Corporation Home Page, http://www.ubicom.com
• 16: Triscend Corporation, A7 CSoC family: http://www.triscend.com/products/indexA7.html
• 17: Hitachi, HD44780U (LCD-H) Dot Matrix Liquid Crystal Display Controller/Driver, ADE-207-272(Z) '99.9, Rev. 0.0.
• 18: OKI Semiconductor, Dot Matrix LCD Controller with 16-dot Common Driver and 40-dot Segment Driver MSM6222B-xx. Version November '97.
• 19: OKI Semiconductor, 80-dot Common/Segment Driver MSM5260. Version November'97.

INDEX TERMS

Primary Classification:
  D. Software
  D.4 OPERATING SYSTEMS

Additional Classification:
  B. Hardware
  B.2 ARITHMETIC AND LOGIC STRUCTURES

General Terms:
Design, Experimentation, Management, Theory

Keywords:
embedded processors, reconfigurable architectures, software peripherals