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8085 Articles
Page 9 of 36
Interfacing 8251 USART with 8085 Microprocessor
The 8251 chip is Universal Synchronous Asynchronous Receiver Transmitter (USART). It acts as a mediator between the microprocessor and peripheral devices. It converts serial data to parallel form and vice versa. This chip is 28 pin DIP.The pin description of 8251A chipPinDescriptionD0 - D7parallel dataC/DControl register or Data buffer selectRDRead ControlWRWrite controlCSChip SelectCLKclock pulseRESETResetTxCTransmitter ClockTxDtransmitted dataRxCReceiver ClockRxDReceiver DataRxRDYReceiver ReadyTxRDYTransmitter ReadyDSRData Set ReadyDTRData Terminal ReadySYNDET/Synchronous Detect/BRKDETDetectBreakRTSRequest to send DataCTSClear to send DataTxEMPTYTransmitter EmptyVccVcc (5V)GNDGround(0V)Now let us see the functional block diagram of the 8251 chip.There are five different sections in this diagram. These sections are as follows −Read/ Write control logicTransmitter ReceiverData Bus ...
Read MoreEI and DI instructions in 8085
In 8085 is having five internal interrupt signals that correspond to the five external interrupt pins. And these interrupts are only recognized only when the internal interrupt signal is activated, the 8085 gets interrupted, provided higher priority internal interrupt signals are not active at the same time. The 8085 checks all these internal interrupt signals in the penultimate clock cycle of the last machine cycle of instruction.With in 8085, there is a flip-flop called IE flip-flop. Here IE stands for Interrupt Enable. 8085 interrupt system is disabled whenever this flip-flop is reset to the 0 states. That is, even if ...
Read MoreSIM and RIM instructions in 8085
In 8085 Instruction set, SIM (Set Interrupt Mask) and RIM (Read Interrupt Mask) instructions can perform mask and unmask RST7.5, RST6.5, and RST5.5 interrupt pins and can also read their status. In 8085 Instruction set, SIM stands for “Set Interrupt Mask”. It is 1-Byte instruction and it is a multi-purpose instruction. The main uses of SIM instruction are –Masking/unmasking of RST7.5, RST6.5, and RST5.5Reset to 0 RST7.5 flip-flopPerform serial output of dataMnemonics, OperandOpcode(in HEX)BytesSIM301When SIM instruction is executed then the content of the Accumulator decides the action to be taken. So before executing the SIM instruction, it is mandatory to initialize ...
Read MoreSIM instruction in 8085
In 8085 Instruction set, SIM stands for “SetInterrupt Mask”. It is 1-Byte instruction and it is a multi-purpose instruction. The main uses of SIM instruction are –Masking/unmasking of RST7.5, RST6.5, and RST5.5Reset to 0 RST7.5 flip-flopPerform serial output of dataMnemonics, OperandOpcode(in HEX)BytesSIM301When SIM instruction is executed then the content of theAccumulator decides the action to be taken. So before executing the SIM instruction, it is mandatory to initialize Accumulator with the required value. The meaning and purpose of the various bits of the accumulator when SIM is executed has been depicted below – Note that except bit 5, which is a ...
Read MoreRIM instruction in 8085
In 8085 Instruction set, Read Interrupt Mask. It is a 1-Byte multi-purpose instruction. It is used for the following purposes.To check whether RST7.5, RST6.5, and RST5.5 are masked or not;To check whether interrupts are enabled or not;To check whether RST7.5, RST6.5, or RST5.5 interrupts are pending or not;To perform serial input of data.Mnemonics, OperandOpcode (in HEX)BytesRIM201To get the status information about the interrupt system, Read Interrupt Mask instruction provides status information about interrupt system and this instruction can be used for serial input of data. Through this RIM instruction, 8085 can know which interrupt is masked or unmasked, etc. The ...
Read MoreHistory of the Integrated Circuit
An electronic circuit is a group of electronic components connected for a specific purpose.A simple electronic circuit can be designed easily because it requires few discrete electronic components and connections. However, designing a complex electronic circuit is difficult, as it requires a number of discrete electronic components and their connections. It is also time taking to build such complex circuits and their reliability is also less. These difficulties can be overcome with Integrated Circuits.To define Integrated Circuit (IC) we can consider that If multiple electronic components are interconnected on a single chip of semiconductor material, then that chip is called ...
Read More4-bit microprocessors
In the 4-bit microprocessor or computer architecture will have a data path width or a highest operand width of 4 bits or a nibble. And also these architectures or microprocessors typically will have a matching register file with registers width of 4 bits and 4-8-bit wide addresses.Most of the first microprocessors during the early 1970s had 4-bit word sizes. Both the Intel 4004, the first commercial microprocessor, and the 4040 had a 4-bit word length, but had 8-bit instructions. Some of the first microcontrollers such as the TMS1000 made by Texas Instruments and NEC's μPD751 also had 4-bit words. 4-bit ...
Read More8-bit microprocessors
In computer architecture, 8-bit integers, memory addresses, or other data units are those that are 8 bits (1 octet or 1 Byte) wide. Also, 8-bit CPU and ALU architectures are those that are based on registers, address buses, or data buses of that size. 8-bit is also a generation of microcomputers in which 8-bit microprocessors were the norm. Mainly we can consider 8-bit microprocessor means 8-bit data or information bus.for controlling a CRT display, Federico Faggin and his team at Intel designed a chip produced by Computer Terminals Corporation. Later this chip was called as Datapoint. This chip did not ...
Read MoreModern Microprocessors
In 8085 Instruction set, In the year 2001, Intel introduced the Itanium processor is the first in a family of 64-bit products. It is capable to meet up most demanding enterprise and high-performance computing applications like e-Commerce security transactions, mechanical computer-aided engineering, large databases and sophisticated scientific and engineering computing.Intel Centrino mobile technology is designed specifically for portable computing, with built-in wireless local area network (LAN) capability and breakthrough mobile performance. It enables extended battery life and thinner, lighter, mobile computers and it has mainly three components. They areThe Intel Pentium M processor, introduced from 2003The Intel 855 chipset family ...
Read MoreMicrocontrollers and Digital Signal Processors
A Microcontroller is a small and low-cost microcomputer, which is designed to perform the specific tasks of embedded systems like displaying microwave’s information, receiving remote signals etc.The general microcontroller consists of the processor, the memory (RAM, ROM, EPROM), Serial ports, peripherals (timers, counters) etc.Types of MicrocontrollersMicrocontrollers are divided into various categories based on memory, architecture, bits and instruction sets. Following is the list of their typesBit − Based on bit configuration, the microcontroller is further divided into three categories.8-bit microcontroller − This type of microcontroller is used to execute arithmetic and logical operations like addition, subtraction, multiplication division, etc. For example, ...
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