Tuesday, August 10, 2010

Microprocessors and Microcontrollers 6th Aug.


This micro will give you macro problems.

Two types of microprocessors are there
1. 8085
2. 8086

A15-A0 - Address Bus
D7-D0 - Data Bus
So total pins- 16+8=24

Multiplex address and data buses- AD7 - AD0 A15-A8

ALE- Address latch enable

when ALE is:

High- Multiplexed address data bus represent Address Bus
Low- Multiplexed address data bus represent Data Bus




PIN DIAGRAM OF 8085

I got this from the net.....

S1 and S0 are Status Signals

S1 S0
1 0 ------------->Read

0 1 -------------> Write
For Memory read For Memory Write
============ ===============

IO/M' 0 IO/M' 0
RD' 0 WR' 0
S1 S0 1 0 S1 S0 0 1


INTERRUPT

Maskable
Ex-RST 7.5,RST 6.5, RST5.5, INTR

Non-Maskable
Immediate response required here Ex- TRAP


->Microprocessor works at half the frequency of the Crystal Oscillator

Reset In - if other device wants to reset the microprocessor
Reset out- if microprocessor wants to recess some other device
Clk out - for synchronising other devices to that of the microprocessor
S1D - Serial input data
S0D - Serial Output data


both S1D and S2D are used for modem.



HEX ADDITION
=============

Remember in Hex-

Decimal Hex
0-9 0-9
10-15 A-F

So for addition of hex...
we will follow the following steps
-> add normally as u do
-> if addition succeeds 10 then start using A,B,C.......
-> if addition succeeds 15 then take 1 as carry and begin counting from 0,1,2......,A,B.....

So,
9+1=A
9+2=B
.
.
.
9+6=F
9+7=0 and Carry 1
9+8=1 and Carry 1

Now remember these things:

F + any number n = (That no. - 1) i.e. (n-1) with carry

ex- F+6=5 carry 1

0 + any number n = (That no.) i.e. n with carry if there is any

Problem:


A B C D
+ E F 5 7
-------------------
1 9 B 2 4


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