new to microcontroller

[angadaria]

hi guys.. i m little bit confused as why we use serial communication instead of parallal port communication?
i know serial communication is preffered over long distance communication to reduce the cost of lots of hardware used by the parallal communication. i think there would be another more acceptable and valid reason for using serial communication....
please help...
thanks and regards

 

[keith1200rs]

It depends on which serial communications you are talking about but in general it is down to reduced I/O count i.e. pins. Consider the number of pins required to talk to a dozen parallel devices compared to if they were all on one I2C interface.

Keith

 

[yadavvlsi]

At first glance, it would seem that parallel ports should be able to send data much faster than serial ports. At first glance, it would seem that parallel ports should be able to send data much faster than serial ports.
However, parallel ports suffer extremely from inter-symbol interference (ISI) and noise, and therefore the data can be corrupted over long distances. Also, because the wires in a parallel system have small amounts of capacitance and mutual inductance, the bandwidth of parallel wires is much lower than the bandwidth of serial wires. We all know by now that an increased bandwidth leads to a better bit rate. We also know that less noise in the channel means we can successfully transmit data reliably with a lower Signal-to-Noise Ratio, SNR.
If, however, we bump up the power in a serial connection by using a differential signal with 2 wires (one with a positive voltage, and one with a negative voltage), we can use the same amount of power, have twice the SNR, and reach an even higher bitrate without suffering the effects of noise. The serial communication may be faster than the parallel one, provided the bits leave the transmitting device at a much higher speed. An example of such is the ATA 2 Serial port that however serial can reach a transfer rate of up to 300 MB/s, while the traditional IDE port [P-ATA] goes to 133 MB/s at the most. USB cables, for instance, use shielded, differential serial communications, and the USB 2.0 standard is capable of data transmission rates of 480Mbits/sec. USB 3.0 has transmission speeds of up to 5 Gbit/s, which is 10 times faster than USB2.0 (480 Mbit/s).!!!

In addition, because of the increased potential for noise and interference, parallel wires need to be far shorter than serial wires. Consider the standard parallel port wire to connect the PC to a printer: those wires are between 3 and 4 feet long, and the longest commercially available is typically 25 feet. Now consider ethernet wires (which are serial, and typically unshielded twisted pair): they can be bought in lengths of 100 feet, and a 300 foot run is not uncommon!

The complications of using Parallel data transfer is that that many wires are required as the width of bus. E.g : A 32 bit PCI bus would have 32 wires and the controls are required for each. In serial communication, just two wires will do the mojo. Also, as the speed of data transfer increases, the e.m disturbances also increases, making parallel data transfer very difficult.

Another problem with parallel communication is that the bits may not reach the destination at the same time. The various reception time of the several bits makes the device wastes time having to wait for all the bits to arrive, which may represent a significant fall in performance.

Finally, parallel data tx. is semi duplex or half duplex, whereas serial data tx. is full duplex. In the serial communication, since it only uses two wires, the manufacturers usually make four wires available, two for the transmission and two for the reception of data. That makes it possible for the simultaneous transmission and reception of data. Such architectural difference alone makes the serial communication about twice as fast as the parallel communication.

 

[angadaria]

hi yadavvlsi,
thanks for the great explanation...i need your help once more...
what would happen if we keep executing the PUSH and POP instruction once stack pointer reaches 7F and 08 respectively?would be ignore all the further PUSH and POP instructions or what?

 

[yadavvlsi]

I think you are talking about 8051 microcontroller. If execute PUSH instruction after stack pointer reaches 7F address. It will not stop there. It roll down to 00 and over write data at that location. It is always programmer's responsibility to take of stack pointer doesn't overflow.

 

[angadaria]

i m sorry to mention about the controller, thanks a lot for great help once again.
is there any website or which book would u recommend to get the deep knowledge about 8051 controller?
thanks and regards

 

[ckshivaram]

mohammed ali mazidi is one of the best book....
also read "Final Word on 8051". the best document you can ever get...

also visit 8052.com - The Online 8051/8052 Microcontroller Resource - 8052.com and go through their tutorials.

 

[yadavvlsi]

You can refer:
1.The 8051 microcontroller by Kenneth J. Ayala.
2.The 8051 Microcontroller And Embedded Systems Using Assembly And C, by Mazidi
3. Programming and customizing the 8051 microcontroller by Michael Predko
If you are familiar with assembly and C programming go for Ayala else start with Mazidi..

 

[ckshivaram]

Dont go for ayala... it has many wrong information in it..

---------- Post added at 09:20 ---------- Previous post was at 09:12 ----------

I have already pointed out it to author and also adviced many universities to stop prescribing this book as it gives wrong information to readers when we take interview to others....

compared to application notes and information from manufacturers this book has published wrong information.......

 

[angadaria]

i m familier with C ...so let's see will start with ayala....

---------- Post added at 19:22 ---------- Previous post was at 19:20 ----------

well thanks for your information....

 

[Tahmid]

Since SATA was brought into this, it might be interesting to note that SATA revision 3.0 can transfer data at a max of 6.0Gbps.

---------- Post added at 22:09 ---------- Previous post was at 21:53 ----------

i m familier with C ...so let's see will start with ayala....

It has already been mentioned that this book contains errors:

Dont go for ayala... it has many wrong information in it..

I have already pointed out it to author and also adviced many universities to stop prescribing this book as it gives wrong information to readers when we take interview to others....

compared to application notes and information from manufacturers this book has published wrong information.......

 

[angadaria]

hi guys,
right now i started using edsim51 simulator for 8051. can anyone help me to configure the lcd module ?
kindly assist....

thanks and regards