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Friday, September 5, 2014

ATMEL 8051 INSTRUCTION SET


Instruction Set
Program Status Word (PSW)
-contains several status bits that reflects the current state of the CPU
*Carry bit 
- carry bit in arithmetic operations serves as the “Accumulator” for a number of Boolean operations
*Auxiliary Carry (for BCD operations)
*2 Register Bank - selects bits
*Overflow flag
*2 user-definable status flags
*Parity bit – 1 if odd, 0 if even
Addressing Modes
*Direct Addressing
-operand is specified by an 8-bit address field in the instruction
-128 lowest bytes of internal Data RAM and SFRs can be directly addressed

*Indirect Addressing
-specific a register which contains the address of the operand
-Both internal and external RAM can be directly addressed

*Register Instructions
-Register banks R0 through R7, can be accessed by certain instructions which carry a 3-bit register specification within the opcode of the instruction. Instructions that access the registers this way are code efficient.

*Register-specific Instructions
-The opcode does itself. Instructions that refer to the accumulator as “A” assemble us accumulator-specific opcode.

*Immediate Constants
-The value of a constant can follow the opcode in Program Memory.
Ex. MOV A, #100
-Can also be specified as 64 in the digits.

*Indexed Addressing
-Only Program Memory can be accessed with indexed addressing, and it can only be read.
-Reading look-up tables in Program Memory.

Arithmetic Instruction
ADD 7F # (direct addressing)
ADD A, @ R0 (indirect addressing)
ADD A, R 7 (register addressing)
ADD, # 127 (immediate constant)
Logical Instructions
The instructions that perform Boolean operations (AND, OR, Exclusive OR, NOT) on bytes perform the operation on a bit-by-bit basis.
Data Transfers
*Internal Ram
-moving data around within the internal memory spaces, and the addressing modes that can be used with each one.
*External RAM
-Instructions that access external Data Memory. Only indirect addressing can be used.
Lookup Tables
-Instructions access only Program Memory, the lookup tables can be read, not updated.
Boolean Instructions
-Instructions that access these bits are not just conditional branches, but a complete menu of move, set, clear, compliment, OR and AND instructions.
*Relative Offset
Jump Instructions
-Conditional Jumps –Unconditional Jumps

Reference:
ATMEL 8051 Microcontrollers Hardware Manual. Atmel Corporation 2005.

48 comments:

Unknown said...

good definitions for each instructions but I wish to see examples so that it will be more understandable =)

Unknown said...

Mam Pau, Pakiulit ulit to ha sa mga students mo. :P

Anonymous said...

Yah! I'm also looking forward for some examples. Thanks!

Anonymous said...

this is great! this blog will help us in our future lessons regarding this topic.. :3
thank you.. hope you continously post helpful information with this blog..

im also hoping to explain how does that codes work??

Anonymous said...

this is great! this blog will help us in our future lessons regarding this topic.. :3
thank you.. hope you continously post helpful information with this blog..

im also hoping to explain how does that codes work??

Anonymous said...

this is great! this blog will help us in our future lessons regarding this topic.. :3
thank you.. hope you continously post helpful information with this blog..

im also hoping to explain how does that codes work??

Anonymous said...

this is great! this blog will help us in our future lessons regarding this topic.. :3
thank you.. hope you continously post helpful information with this blog..

im also hoping to explain how does that codes work??

Unknown said...

The definitions clarifies the details about the ATMEL and it will help us to really understand more the instructions in programming it.

Anonymous said...

It is also creepy to know these instruction codes!!

Unknown said...

i can't wait to hear ma'am pau to discuss this. so that,I will understand this as clear as mineral water.. hahaha
So that I can learn more.. thank for instant information..

Unknown said...

What a precise and convenient definitions and examples you have!

To be honest, I'm kinda wondering what's the meaning of sharp (#) in a sample program that I have surf in the internet, and in some point it just means "immediate"! I was laughing at myself knowing that my forehead is so knot the whole time looking at the sharp (#) symbol, so thank you very much because my forehead is saved from forehead knot distortment (if there exists)

XD

-Baroque.Works- said...

Actually it's a little bit confusing to understand all the Instruction Set of ATMEL 8051 in just a glimpse. Maybe I can appreciate more all of this when we started to make a program just like SAP, Motorola and Assembly.
-Dennis

Anonymous said...

My first reaction was like ..
HMMMMMMMM (loading)

Seriously, I'm a bit puzzle with this Instruction set of ATMEL 8051. I'm preparing myself and I'm looking forward for more actual explanation.
I know it's hard that's why I sincerely giving a credit of appreciation by heart for this instruction set.

-anaPANGET (di na naman anonymous)

Unknown said...

http://www.keil.com/dd/docs/datashts/atmel/at_c51ism.pdf

data sheet of instruction set. :)

ALABZ said...

wow! this is the advanced used of technology... it will help us in our future lesson.. the definitions are detailed but I'm looking for examples of pictures/images of this topic to help my ideas explore and understand clearly what its stated.

ALABZ said...

...Thank you mam.. this is a good example to take the learner in advance topic..

Unknown said...

..it was a advance study for me. i wish it will have more example so we could understand more. I know it will help us in our incoming lesson

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Unknown said...

very good definitions of terms. it clarifies how to program and help as to be familiar for the next topic to be discuss.

thank you ma'am:)

Unknown said...


www.atmel.com/dyn/resources/prod_documents/doc0509.pdf


Unknown said...

additional info .. www.atmel.com/dyn/resources/prod_documents/doc0509.pdf

Unknown said...

additional info.
https://www.newbiehack.com
try this one also.

Unknown said...
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Unknown said...

Thanks for sharing with us. Really good post.

Jeanny Rose Lao-ang said...

I am looking forward for further discussions regarding this topic. Looks like I have to read more about this. Thanks though for the information. :)

Unknown said...

The terms indicated in this post is somewhat similar to the terms shown in SAP 1-3 and even in motorola, looking forward for the discussion of this subject matter :)

Anonymous said...

It is explained in a very light approach where students or beginners can easily understand the topic.
-ERJ

Anonymous said...

It is much easier to understand if we can apply it in our hands-on activities.
-ERJ

Unknown said...

This topic on your blog is worth reading. I learned new stuffs. But I hope the are examples so that we are able to understand it more.

Unknown said...

This blog "ATMEL 8051 INSTRUCTION SET" will set as a guide to us to our next lesson which is about microcontroller. I'm looking forward for the easy and complicated examples. Thanks in advance ! :)

Here is some information about 8051 instruction set ..
The 8051 has 255 instructions – Every 8-bit opcode from 00 to FF is used except for A5.
The instructions are grouped into 5 groups – Arithmetic – Logic – Data Transfer – Boolean – BranchingMicroprocessors :)

Bagz :) said...

This instruction sets serves as a great help to cope up and perform the next discussion :)
# this is it :3 hahahaha

~Peejay Jet~ said...

AMTEL? oh comeon! that's as simple as possible! haha but before SAS, mam pau will teach us first.. thank you your blog ;) it let us know what we are going to tackle the next lessons. :)

~ALPAS Judith~

~Peejay Jet~ said...

Thank you for your blog ;) correction to my first comment ;)

~ALPAS Judith~

Unknown said...

i see that its a further explanation of ATMEL 8051 Instruction Set.

again, it's coherent and handy :)

Unknown said...

Good definitions of every instruction set! But I think I need to research more about this to fully understand it. Thank you for this, anyway. :)

Unknown said...

You defined the terms well. It is a good material for advance reading and reviewing. Thank you for this! :)

Unknown said...

Each terms here are almost modefiftned clearly and precisely. It is anythings!i

Unknown said...

good definition of terms to start with :)


for additional info check this one
http://www.atmel.com/images/doc0509.pdf

Unknown said...

are you going to discuss this on us ma'am ?

hope you do for us to learn this instruction set

seriously im not so good at programming so this would be a help for me

thanks mam

~~~~~~~Azzir Adriano

Unknown said...

This is a useful information that will help beginners in programming, just like me..
I'm looking forward for more set of informations. This is a nice blog. :)
A very expedient one.. ^_^

Ronalyn A. Balando said...

Very informative. I'll try to read some more instruction set like this. It will help a lot. Thanks for the information.

Unknown said...

sorry for being late .. but late is better than never...
this ATMEL8051 is seems to be an exciting and interesting subject,, i hope this will not make things complicated and perplexed ...but it will enhance my logical "thingking" skill and help me more on appreciating the wonder world of computer....

Jean Carol Colico said...

Informative..and instruction sets and different addressing modes are well stated..interesting but we are looking forward for some examples to further understand this topic..:)