Serial Communication RS2. Basics max. Embedded. Serial Communication RS2. Basics. In the previous post, we discussed about the basics of serial communication. In this post, we will learn about the RS 2. This is the protocol you will be using the most when involving microcontrollers like AVR. As we proceed ahead in this post, we will deal with the concept of level conversion and towards the end, we have something interesting and practical for you the loopback test Contents. RS 2. 32 Basics. RS 2. Recommended Standard 2. Electronic Industries Association EIA for connecting serial devices. In other words, RS 2. RS 2. 32 is the interface that your computer uses to talk to and exchange data with your modem and other serial devices. The serial ports on most computers use a subset of the RS 2. C standard. RS 2. DB9 port commonly known as serial port, however earlier it was used over the DB2. We will have a look at both of them here. Convert Mat File To Csv. RS 2. 32 over DB 9. The pin configuration of DB 9 port is as follows. Yes, it looks exactly like in fact it is the serial port you would find in older computers. RS2. 32 DB9 Connector. DB9 Connector Pins. The pin description for the RS 2. DTR data terminal ready When terminal is turned on, it sends out signal DTR to indicate that it is ready for communication. DSR data set ready When DCE is turned on and has gone through the self test, it assert DSR to indicate that it is ready to communicate. RTS request to send When the DTE device has byte to transmit, it assert RTS to signal the modem that it has a byte of data to transmit. CTS clear to send When the modem has room for storing the data it is to receive, it sends out signal CTS to DTE to indicate that it can receive the data now. DCD data carrier detect The modem asserts signal DCD to inform the DTE that a valid carrier has been detected and that contact between it and the other modem is established. RI ring indicator An output from the modem and an input to a PC indicates that the telephone is ringing. It goes on and off in synchronous with the ringing sound. Rx. D Received data The Rx. This is the newest revision of our FTDI Basic. We now use a SMD 6pin header on the bottom, which makes it smaller and more compact. Functionality has remained the same. Serial Communication Introduction. Hey folks Guess what Its now time for one of the most desired tutorials on maxEmbedded the Serial Communication series Arduino IDE Integrated Development Environment, currently in version 1. Arduino boards. It has an easytolearn intuitive. List of USB IDs Maintained by Stephen J. Gowdy If you have any new entries, please submit them via http or send. Serial Communication RS232 Basics. In the previous post, we discussed about the basics of serial communication. In this post, we will learn about the RS232. D pin is the Data Receive pin. This is the pin where the receiver receives data. Tx. D Transmitted data The Tx. D pin is the Data Transmit pin. This is the pin through which data is transmitted to the receiver. Lauterbach is the worlds largest producer of complete, modular and upgradeable microprocessor development tools worldwide with experience in making world class. The MSP430 is a mixedsignal microcontroller family from Texas Instruments. Built around a 16bit CPU, the MSP430 is designed for low cost and, specifically, low. SEGGER Microcontroller is a fullrange supplier of software, hardware and development tools for embedded systems RTOS, IDE, debug probe, stacks. For technical support on MSP430 please post your questions on The MSP430 Forum. Please post only comments about the article Open Source Projects MSP430 here. The objective of the sub1GHz wiki is to provide extensive selfhelp resources including technical collateral and information for CC1310CC1350 SimpleLink. Msp430_fet_tools.PNG' alt='Msp430 Serial Bootloader' title='Msp430 Serial Bootloader' />RS 2. DB 2. The pin configuration of DB 2. Yes, it looks exactly like the parallel printer port that you would find in older computers It is however worth noting that the DB 2. RS 2. 32 or parallely. The pinouts are different in each case. The pinout for RS 2. DB 2. 5 is shown below thanks Thomas and Aaron for clarification. RS2. 32 DB2. 5 Connector. DB2. 5 Connector Pins. As we can see, most of the pins are similar to that of a DB9 port. If you notice, we see that in DB2. Tx. D and Rx. D pairs of pins. Now what does this meanIn simple words, it means that serial communication through the DB 2. Thomas. NOTE Another important thing to note is that the simplest way to in which a microcontroller can communicate to a PC is through Rx. D, Tx. D, and Ground Pins. And this is what we will be doing here and hence forth in upcoming posts. The other pins are not of much use to us, for now. Now this was something about RS 2. Our next topic is level conversion. Btw, have you heard of TTL Sounds familiar, but what is TTLLets read on Logic Level Families. By Logic Level one means the range of voltage over which a high bit 1 and a low bit 0 is accepted in a particular IC, gate, etc. Various logic levels have been standardized, out of which the most popular ones are 1. TTLTTL stands for Transistor Transistor Logic. These days TTL is the most widely used logic. TTL is mostly used in ICs and gates, like 7. A major drawback of the TTL logic is that most of the devices working on the TTL Logic consume a lot of current, even individual gates may draw up to 3 4 m. A. In TTL Logic, a HIGH or 1 is 5 volts, whereas a LOW or 0 is 0 volts. But since attaining exact 5 volts and 0 volt is practically not possible every time, various IC manufactures define TTL logic level range differently, but the usual accepted range for a HIGH is within 3. LOW is 0 0. 8 volts. LVTTLLVTTL stands for Low Voltage Transistor Transistor Logic. LVTTL is increasingly becoming popular these days, because of the nominal HIGH voltages, and hence lesser power consumption. By lowering the power supply from 5v to 3. There are several transistors and gates, which work on LVTTL logic. Atmels Atmega microcontrollers are designed to work on both, LVTTL and TTL, depending upon the VCC supplied to the IC. In LVTTL Logic, a LOW is defined for voltages 0. V 1. 2. V, and High for voltages 2. V 3. 3. V, making 1. V2. 2. V undefined. RS 2. 32. RS2. 32 is also one of the most popular logic. Though now quite old, it is still in use. In RS 2. 32 logic, a HIGH 1 is represented within 3. V 2. 5 V, whereas a LOW 0 is in between 3. V 2. 5 V, making 3. V to 3. V undefined. Weird isnt it But thats how it is defined Apart from these, there are many other logic families like ECL, RTL, CMOS, LVCMOS, etc. At present, we are not much concerned about them. You can refer to this article to know more about them. Level Conversion TTLRS2. So what is logic level conversion To interconnect any two logic level families, their respective HIGHs and LOWs must be same else they wouldnt work. For example, when we want to interconnect two devices, one of which works over TTL and the other over RS2. HIGH of TTL which is 3. HIGH of RS2. 32 which is 3v 2. LOW of TTL 0v0. RS2. So you see, here lies the problem If we do not convert the logic levels in this case then the LOW signal of TTL would be interpreted as a HIGH in RS2. The Solution. One solution is to use additional pull up resistors, or to use Zener diodes. A better solution is the use of ICs that directly converts logic levels. Luckily logic level conversion is quite simple these days with the use of ICs like MAX2. CP2. 01. 2 We would talk about all these solutions one by one. Zener Diodes. Zener diodes are widely used to regulate voltage between two points. When Zener diode is used in reverse bias in series with a suitable resistor, and a voltage breakdown voltage is applied across the terminals of the Zener resistor pair, then a voltage V Zener Voltage appears across the terminals of the Zener diode, while the rest of the voltage appears across the terminals of the resistor. The simple circuit below shows how to use Zener diodes to convert logic levels from TTL to LVTTL Note that this circuit is only applicable for high to low logic level conversions Bidirectional Logic level converters are easily available in the market. Some of the websites selling them are Adafruit, Freetronics, Sparkfun, Embedded Market etc. IC MAX2. 32. MAX2. ICs were invented by Maxim. These IC packages are used to convert TTLCMOS logics to RS2. All we need are some passive components, and we are done Below is the circuit diagram of the MAX2. IC. Level Conversion using MAX2. MAX2. 32 is used to convert TTL to RS2. But these days, USB is the most used protocol Everything runs on USB be it printer, scanner, displays or anything But how to convert USB to UART One way is USB  TTL  UART. The other way is to use USB UART bridges which directly convert USB UART. They are widely and easily available these days. Here are some of the websites Robokits, e.