Registers of 8051 pdf

Divide the time reload value by 2 to achieve exact 20 ms delay value. It comes out to be Convert it in to Hexadecimal Format. Load the upper timer register with High byte and lower timer register with Low byte. Download File. You must be logged in to post a comment. You can use them as counters, event counters. Since we can use them as counters so we can easily generate time-delays and baud rate for serial UART communication.

They can also be used as interrupt counters. Both the microcontroller timers 0 and 1 are bit wide. These two registers TH and TL are timer high byte and timer low byte registers. These are bit registers. Recall timer counter can count up to and 16 bits cover in binary.

Since 89c51,89c52 is an 8-bit microcontroller, so to load we need two registers one representing the high byte and other the low byte. TH0 and TL0 are byte addressable only.

The most important bits of the timers TRx and TFx are also in it. TRx timer run and TFx timer overflow bits which we use in almost all our timer applications are in it. Difficulty Beginner Intermediate Advanced. Explore Documents. Uploaded by San Ram. Did you find this document useful?

Is this content inappropriate? Report this Document. Flag for inappropriate content. Related titles. Carousel Previous Carousel Next. Microprocessor and Micro Controller Lecture Notes. Operatingsystems Concepts Silberschatzgalvinslides Phpapp What is the Difference Between Microcontrollers and Jump to Page. Search inside document. Types of Interrupts in Microcontroller Interrupts are the events that temporarily suspend the main program, pass the control to the external sources and execute their task.

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Ashoka Vanjare. Diana Rose. Kamran Ahmed. ACC is usually accessed by direct addressing and its physical address is E0H. Accumulator is both byte and bit addressable. You can understand this from the figure shown below. To access the first bit i. Now if you want to access the second bit i. The major purpose of this register is in executing multiplication and division.

If you are familiar with , you may now know that multiplication is repeated addition, where as division is repeated subtraction. Now here in you can do this with a single instruction.

Note: Follow this link if you are interested in knowing about differences between a microprocessor and microcontroller. Register B is also byte addressable and bit addressable.

To access bit o or to access all 8 bits as a single byte , physical address F0 is used. To access bit 1 you may use F1 and so on. Please take a look at the picture below. Note: Register B can also be used for other general purpose operations. As you may already know, there are 4 ports for If you are unfamiliar of the architecture of please read the following article:- The architecture of Data must be written into port registers first to send it out to any other external device through ports.

Similarly any data received through ports must be read from port registers for performing any operation. All 4 port registers are bit as well as byte addressable. Take a look at the figure below for a better understanding of port registers. Known popularly with an acronym SP, stack pointer represents a pointer to the the system stack. Stack pointer is an 8 bit register, the direct address of SP is 81H and it is only byte addressable, which means you cant access individual bits of stack pointer.