Pic and serial communication

I really appreciate your contribution. I remember you have stated that RCIF bit can only be clared by hardware. Then why did you clear this bit by writing 0 to it? Generally, interrupt flag bits have to be cleared in software after servicing the interrupt request inside the isr. Check it out and tell me what you will get! These lines are from receiver firmware.

Were these lines necessary? On the on the other hand, the init fubction can not be defined without declaring it at the bedinning. The declaration is still important. Unless you move the function definition block to be above the main. In this case, no declaration is needed. Thanks Khaled for such in depth tutorials. I am using them together with PIC micro-controller datasheet and I always come right.

One question though, what is difference between computer science and computer engineering? My code fails because I do not understand how to read a string rather than a single character. I expect I need to disable interrupts and reset pointers etc, but an example of receiving strings using the ISR would be very helpful. Awesome Tutorial. I have come across a very long way to this. So far best Tutorial. UART explained very elaborately.

OR another tutorial may be :. Thank you. Hi Kareem! Nice question. You can also google this subject to get an idea how reading a uart bit 16 times is useful. It helps uart module to make sure that a specific received bit is a 0 or 1. Greatings Khaled. First of thank you for this wonderful website. Hi Edward. Thx for your feedback. I actually still in doubt if that is the issue in your test setup.

HI Khaled Thank you for your time. In the uart tut you refer to your spi tut, however, when I follow the link — Page not Found- I see that on the Tut homepage, clicking on SPI points to the same link with — Page not Found-. Coding 7. Simulation 7. Prototyping 7. TRMT ;. RCIF ;. Data -- ;. Like this: Like Loading Abhishek Kasaudhan says:.

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LM Voltage Regulator 5v. Crystal Oscillator. PICkit2 or 3 Programmer. Add Add Add. Serial Communication. Parallel Communication. Relative Speed. Distance Range. Much Farther. Transfer Method. One bit is transmitted at a time. Bytes are transmitted in parallel, One byte or more at a time. Short distance High-Speed communication such as Computer printers, etc.

Wires Inside. Few wires, all data bits pass only through the same data line. Multiple, more wires, each bit has a dedicated wire. So as to be transmitted all at once. Transmitting the word using serial communication. When using the parallel communication, however, the number of bits will be transmitted at once from one computer to the second computer. Transmitting the word using parallel communication.

In addition to the serial and parallel communications, there are 2 types of communication we will explore:. That means that the transmitter and the receiver are synchronized between them by the same clock frequency. The clock frequency can be transmitted along with the information, while it is encoded in the information itself, or in many cases there is an additional wire for the clock. When using the asynchronous communication - the transmitter and the receiver refraining to transmit long sequences of bits because there isn't a full synchronization between the transmitter, that sends the data, and the receiver, that receives the data.

In this case, the information is divided into frames, in the size of byte. Each one of the frame has:. Frames of information must not necessarily be transmitted at equal time space, since they are independent of the clock. This component can be configured as:.

To enable the serial communication with PIC micro we must set different parameters within two registers: click the links for the explanation of each bit. This information will be stored inside TXREG register, which acts as a temporary buffer storage of information prior to transmission. Transmitting 8 bit data. The received information will be stored in the RSR register, which acts as a temporary buffer storage. Receiving 8 bit data. Suppose we want to transmit the following information: This information is in the size of 9-bit, so there is not enough space to store all the information in the TXREG register.

It is important to note, that first we need to store the 9th bit and only later other 8-bits. This is important because the information of 8 bits may be transmitted immediately once being inside the TXREG register. As a result the transmitted information will be incorrect. In data Transmission, if data can both be transmitted and received, it is a duplex transmission.

In contrast, a simplex transmission only sends data from one device to the other such as from computer to printer. Duplex Transmission can be Half or Full duplex depending upon whether the data transfer is simultaneous or not.

If data is transmitted one way at a time, then it is half duplex. If data can go both ways at the same time then it is Full duplex. PIC microcontroller has a full-duplex, serial mode of Communication. Half and Full-Duplex Transmission. The rate of data in serial data communication is known as bits per second or bps. Usually Baud rate is used instead. However, the baud rate and bps are not necessarily equal.

This is because baud rate is a modern terminology and is defined as the number of signal changes per second. In modems, sometimes a signal change of signal transfers several bits of data. So there is small difference between bit rate bps and baud rate. Different protocols are used in data communication for efficient transfer of data between different devices. In this lab we will be using RS standard protocol. This method of serial communication used by a uController is referred to as TTL serial transistor-transistor logic.

So, you may see where the problem lies in interfacing these two signals. There are a handful of solutions to this problem of voltage converting and inverting. The most common, and easiest solution is just plugging a MAX in between the two devices:. Most modern computers are not equipped with a serial port. Fortunately for you, the lab boards you have been using already has this circuit printed on them.