Uncategorized

Personal Computer System The conventional desktop system comprises a main unit, separate keyboard and mouse, and monitor. The main unit has connectors for these (when wireless peripherals are not available) and universal serial bus (USB) ports for memory sticks, printers, scanners, etc., as well as hardwired (Ethernet), or wireless (Wi-Fi) network interfaces. The circuit board […]
Continue reading…

PC Hardware Inside the PC main unit (Figure 1.2b), the traditional motherboard has slots for expansion boards and memory modules to be added to the system. The power supply and disk drives are fitted separately into the main unit frame. The keyboard and mouse interface are integrated on the motherboard. In older designs, expansion boards […]
Continue reading…

Introduction When using asynchronous serial protocols, such as ‘RS-232’, the two devices that are communicating must agree on a communication frequency (the baud rate) and each device then uses (say) an independent crystal-based clock to ensure that it operates at the required rate. One consequence of this approach is that, if the clocks in the […]
Continue reading…

Example: I2C Temperature sensor interface In this example we consider how to link an 8051 microcontroller to Dallas DS1621 (I2C) temperature sensor. Hardware See Figure 23.4. Software The key software files are in Listings 23.7 to 23.9: all the files required for the project are included on the CD, in the directory associated with this […]
Continue reading…

Example: I2C core library In this section we present a library of core I2C routines (Listings 23.1 to 23.3). In most cases you will need to add some additional functions to use these files with particular I2C peripherals: we illustrate this process in the examples that follow. Please note that not all I2C devices use […]
Continue reading…

Example: I2C EEPROM interface In this example we consider how to link an 8051 microcontroller to a serial EEPROM using an I2C bus. Note that use of such EEPROMs is a common way of retaining system settings after power is removed: the storage is non-volatile, for a period of around 100 years. Hardware The required […]
Continue reading…

I2c peripheral Context ● You are developing an embedded application using one or more members of the 8051 family of microcontrollers. ● The application has a time-triggered architecture, based on a scheduler. ● The microcontroller in your application will be interfaced to one or more peripherals, such as a keypad, EEPROM, digital-to-analog converter, or similar […]
Continue reading…

Example: Keypad library with buffer and fn key support We present here a complete keypad library for the 8051 family. The library has support for function keys (two) and has a buffer facility. The library is intended to work with key- pads as shown in Figure 20.3, but is easily adapted to different keypad layouts […]
Continue reading…

I2c peripheral Context ● You are developing an embedded application using one or more members of the 8051 family of microcontrollers. ● The application has a time-triggered architecture, based on a scheduler. ● The microcontroller in your application will be interfaced to one or more peripherals, such as a keypad, EEPROM, digital-to-analog converter, or similar […]
Continue reading…

Using serial peripherals In Part E we consider how two powerful and influential serial communication protocols (‘I2C’ and ‘SPI’) may be utilized in applications with a time-triggered architecture. Use of these protocols has two main advantages: ● They are designed to allow microcontrollers to be linked to a wide range of different peripherals – memory, […]
Continue reading…