IC BUFFER 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 How do you safely control one or more small, low-power DC loads from a single microcontroller port? Background Suppose we try to […]
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Posts by Farahat
NAKED LED
NAKED LED 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 What is the cheapest way of driving a small number of LEDs with a microcontroller? Background Even in the most basic application, […]
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NAKED LOAD
NAKED LOAD 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 How do you connect a piece of low-voltage (≤ 5V), low-power (≤ 100 mW) DC equip- ment to one of the port […]
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OFF-CHIP CODE MEMORY
OFF-CHIP CODE MEMORY 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 How do you add up to 64 kbytes of external code memory (usually ROM) to your 8051 microcontroller? Background See OFF […]
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Driving DC Loads
Introduction The port pins on a typical microcontroller can be set at values of either 0V or 5V (or, in a 3V system, 0V and 3V) under software control. Each pin can typically sink (or source) a current of around 10 mA. In this chapter, we are concerned with hardware designs that will allow us […]
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Designing embedded systems using patterns:Limitations of existing software design techniques
Limitations of existing software design techniques We begin the main part of this chapter by considering two examples which illustrate the limitations of standard design techniques when used for embedded system development. Cruise-control system As a first example, we will consider a cruise-control system (CCS) for a road vehicle. A CCS is often used to […]
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ON-CHIP MEMORY
ON-CHIP MEMORY 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 How do you create an 8051-based circuit that uses only internal memory? Background Some general background material on memory is presented in […]
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OFF-CHIP DATA MEMORY
OFF-CHIP DATA MEMORY 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 How do you add up to 64 kbytes of external RAM to your Standard 8051 microcontroller? Background To add external data […]
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Reset hardware:RC RESET
RC RESET 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 How do you create a low-cost reset circuit for your 8051 microcontroller? Background As discussed in the introduction to this chapter, the […]
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Reset hardware:ROBUST RESET
ROBUST RESET 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 How do you create a very reliable reset circuit for your 8051 microcontroller? Background See RC RESET [page 68] for some background […]
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