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Articles by Arjun Thakur
Page 41 of 75
Data transfer group in 8051
In 8051 Microcontroller there is 28 different instructions under the Data Transfer Group. In total there are 79 opcodes. The flags are not affected by using the data transfer instructions, but the P (Parity) flag may change if the value of A register is changed using Data Transfer Instruction. Similarly, when a data is transferred to the PSW register, the flags will change.In the following table, we will see the Mnemonics, Lengths, Execution Time in terms of the machine cycle, Number of Opcodes etc.MnemonicsByte CountExecution TimeOpcode CountMOV A, Rn118MOV A, a8211MOV A, @Ri112MOV A, #d8211MOV Rn, A118MOV Rn, a8228MOV Rn, ...
Read MoreHex to ASCII conversion in 8051
Now we will see how to convert Hexadecimal number to its ASCII equivalent using 8051. This program can convert 0-9 and A-F to its ASCII value. We know that the ASCII of number 00H is 30H (48D), and ASCII of 09H is39H (57D). So all other numbers are in the range 30H to 39H. The ASCII value of 0AH is 41H (65D) and ASCII of 0FH is 46H (70D), so all other alphabets (B, C, D, E) are in the range 41H to 46H.Here we are providing hexadecimal digit at memory location 20H, The ASCII equivalent is storing at location 30H.AddressValue...20H0EH21H...ProgramMOVR0, ...
Read More1's complement notation
This is one of the methods of representing signed integers in the computer. In this method, the most significant digit (MSD) takes on extra meaning.If the MSD is a 0, we can evaluate the number just as we would interpret any normal unsigned integer.If the MSD is a 1, this indicates that the number is negative.The other bits indicate the magnitude (absolute value) of the number.If the number is negative, then the other bits signify the 1's complement of the magnitude of the number.Some signed decimal numbers and their equivalent in 1's complement notations are shown below, assuming a word ...
Read More8051 Program to Subtract two 8 Bit numbers
Here we will see how to subtract two 8-bit numbers using this microcontroller. The register A(Accumulator) is used as one operand in the operations. There are seven registers R0 – R7 in different register banks. We can use any of them as the second operand.We are taking two number73H and BDH at location 20H and 21H, After subtracting the result will be stored at location 30H and 31H. AddressValue...20H73H21HBDH...30H00H31H00H...ProgramMOVR0, #20H;set source address 20H to R0 MOVR1, #30H;set destination address 30H to R1 MOVA, @R0;take the value from source to register A MOVR5, A; Move the value from A to ...
Read MoreInterrupt handing in 8051
As we have seen there are five different interrupts in 8051. These interrupts are INT0, INT1, TO, T1, TI/RI.There are six states in each machine cycle. These states are S1 to S6. All of the interrupts are sampled at the end of state S5 of each machine cycle. When the instruction takes more than one machine cycle, then the samples are polled during the next machine cycle. When an interrupt flag is set at the S5 of the first machine cycle, then the polling cycle will find it. The interrupt system generates LCALL instruction to call appropriate ISS.There are some ...
Read MoreInterfacing 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 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 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 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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