Interfacing LCD Microprocessor and Interfacing by Ravinder Nath Rajotiya - May 4, 2022May 4, 20220 Introduction LCD is the most common display devices used in different dedicated applications be it the instrumentation, medical equipment, panels, robotics etc. It is quite easy to interface it with the microprocessors or microcontrollers. We can directly interface a LCD with microcontrollers, however, for interfacing with microprocessors, we need a peripheral device such as 8255. Here in this post we discuss the basics of LCD, its commands, interfacing using 8255 PPI an final a program to initialize LCD to display some user data on it. PIN Diagram of LCD Pin number Symbol I/O Description 1 Vss xx GND 2 Vcc xx +5V 3 VEE Xx Power Supply to control contrats (use POT) 4 RS I RS=0 to select command Register, to allow user to send command to LCD RS=1 to select data register, allowing user to send data for display 5 R/W I R/W=0 : to Write R/W=1: to
Analog to Digital Conversion (ADC) interfacing Uncategorized by Ravinder Nath Rajotiya - May 2, 20220 ADC ADC is used to convert an analog input voltage to its digital equivalent. ADC chip family is ADC080X from National Semiconductors. Some of the ICs are: ADC-0800, ADC-0804: singly analog input channel and 8-bit out bits ADC-0808 and ADC-0809: These are eight analog input inputs with 3-select lines used to select one of eight channel. It also has 8-bit digital output. ADC-0816 : It is an 16-input channel and gives 8-bit digital output signal. Why Analog to Digital Signals in the real world are analog: light, sound, temperature, pressure, acceleration or other phenomenon. So, real-world signals must be converted into digital, using a circuit called ADC (Analog-to-Digital Converter), before they can be manipulated by digital equipment. When you scan a picture with a scanner what
Experiment-5 Reading a number from One Port and Sending it to another Port 8086 Programming by Ravinder Nath Rajotiya - April 15, 2021May 9, 20220 Aim: Write a Program to read 16 bit Data from a port and display the same in another port. Objectives: [ To learn configuring of Key board and display module with 8086 microprocessor using 8255PPI Design algorithm and develop a program for accepting data from oneport and displaying it to LCD connected to other port. Equipment Require: 8255 Display Module, 8086 trainer Kit Theory: A Simple approach We can make use of the 8086 IN and OUT instruction to read the data from the device attached to a port and send the data to another port. We can access the ports using direct addressing or indirect addressing Direct address can be provided in the instruction Indirect address is loaded in DX register. here is simple program statements for the
8255 PPI(Programmable Peripheral Interface) Microprocessor and Interfacing by Ravinder Nath Rajotiya - March 26, 2020April 21, 20220 8255 Programmable Peripheral Interface 8255 is a programmable peripheral interface IC which is used as an interface between the external device and the microprocessor for parallel communication. This IC is a 40-pi IC having three ports known as Port-A(PA), Port-B(PB) and Port-C(PC). these ports can operate in various modes. the complete details is given in the following PPTSs. Features of the 8255: It provide three I/O ports All the three I/O ports are latched Port operation is configurable by programming 8255 i.e. writing a control word in CWR BSR- bit set-reset mode allows individual pins of port C to be controlled to be set or reset. PIN diagram of 8255 8255 PPI is a 40-pin IC, it has three 8-bit ports named PA, PB
8255 Programmable Peripheral Interface Interfacing devices by Ravinder Nath Rajotiya - March 13, 2020May 10, 20210 8255 Programmable Peripheral Interface Introduction: 8085 microprocessor need the interface ICs to interface with the I/O devices. In this lecture we focus on 8255 a programmable peripheral interface. Features of 8255 40 pin IC. 24 I/O pins divided into 3 groups, Port-A, Port-B, and Port-C. Port C can be used as a single 8-bit port or in group of four bits for providing handshake signals for Port-A and Port-B. 8255 can operate in different modes i.e. BSR Mode, and I/O Mode BSR mode is used for controlling individual bits of port C in read/write operation, I/O Mode of Operations are : Mode-0, Mode-1, Mode-2 . Mode-0 is used when simple I/O activity is required on all three ports, Mode-1 is used for handshake mode for Gp-A and G-B ports with