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 […]
Continue reading…
Uncategorized
BJT DRIVER
BJT DRIVER 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 drive DC loads requiring currents of up to around 2A, from the port of an 8051 microcontroller? Background A […]
Continue reading…
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 […]
Continue reading…
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 […]
Continue reading…
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 […]
Continue reading…
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 […]
Continue reading…
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 […]
Continue reading…
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 […]
Continue reading…
Memory issues
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 […]
Continue reading…
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 […]
Continue reading…