Posts by Farahat

Introduction All practical microcontroller-based systems require some form of non-volatile code memory (to store the program code) and some form of volatile memory (to store data and the stack). In many cases, it is possible to create useful applications without adding external memory devices. The first pattern in this chapter (ON – CHIP MEMOR Y […]
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EXTENDED 8051 Context You are developing a microcontroller-based embedded application and have some flexibility in the choice of hardware platform to be used. Problem Should you base your application on an Extended 8051-family microcontroller? Background As we have seen in connection with ST ANDARD 8051 [page 30] and SMALL 8051 [page 41], this long-lived microcontroller […]
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Introduction Early in the life-cycle of most embedded projects, an initial choice of microcontroller must be made. While it may become necessary to change the microcontroller as the project develops, the particular hardware platform that is used will have a substantial impact on many later software and hardware design decisions and development costs can be […]
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CERAMIC RESONATOR Context ● You are developing an embedded application using one or more members of the 8051 family of microcontrollers. ● You are designing an appropriate hardware foundation for your application. Problem When and how should you use a ceramic resonator with members of the 8051–family microcontrollers? Background A ceramic resonator is, like a […]
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Introduction The process of starting any microcontroller is a non-trivial one. The underlying hard- ware is complex and a small, manufacturer-defined ‘reset routine’ must be run to place this hardware into an appropriate state before it can begin executing the user program. Running this reset routine takes time and requires that the microcontroller’s oscillator is […]
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CRYSTAL OSCILLATOR Context ● You are developing an embedded application using one or more members of the 8051 family of microcontrollers. ● You are designing an appropriate hardware foundation for your application. Problem When and how should you use a quartz crystal to create an oscillator for use with members of the 8051 family of […]
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Conclusions In this second brief introductory chapter, we have argued that developers of embedded applications can benefit from pattern-driven design techniques not least because many embedded projects require the developer to have both knowledge of software design and from a range of related technical and engineering fields. Four points should be made as we conclude […]
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Introduction All digital computer systems are driven by some form of oscillator circuit. This circuit is the ‘heartbeat’ of the system and is crucial to correct operation. For example, if the oscillator fails, the system will not function at all; if the oscillator runs irregularly, any timing calculations performed by the system will be inaccurate. […]
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SMALL 8051 Context You are developing a microcontroller-based embedded application and have some flexibility in the choice of hardware platform to be used. Problem Should you base your application on a Small 8051-family microcontroller? Background The desktop microprocessor market is characterized by constant demands for increased power. As a result, processors become obsolete after two […]
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Patterns for time-triggered embedded systems We found the software patterns described by Gamma et al. (1995) to be useful. However, they were insufficiently specialized for use with time-triggered embedded systems. We therefore began to assemble a collection of patterns based on our experience with the development of applications for the 8051 and other families of […]
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