Majid, one good practice when you're testing communication between two embedded systems (A and B) is to check each one with a terminal first.
Assuming A is sending to B and B receives and does something on IO port, test first the TX of A to the computer terminal, then RX of B from the computer terminal. After that, only if each one works ok, connect TX/RX of A with B. Some good free terminals for this job (search for:) Realterm, Teraterm, Termite. You may also need a hardware converter which depends on your computer (if you have a real COM port with RS232 levels or just an USB/RS232 with 3.3V or 5V levels). This approach will protect you from a lot of trouble and make you understand if a byte, a word, an ASCII or something else is truly sent/received and was sent/received in the right order. Simplify your work by sending and receiving ASCII symbols first and then understand all the used procedures from the libraries (this is mandatory to understand which is your fault/misunderstanding or which is the software bug... there are bugs in any software...:) ). On Sat, Apr 24, 2021 at 8:36 AM Rob CJ <[email protected]> wrote: > Hi Majid, > > If you want to send an integer value you indeed have to send it in bytes. > But that thouls be faily easy with JAL. > > If have for example a variable of type word you can do the following > > var word my_word_variable > var byte my_byte_variable_low at my_word_variable > var byte my_byte_high at my_word_variable + 1 > > You can then send both 'my_byte' variables separately and in the other PIC > you do the same, read the two bytes which are mapped to a word. > > Als see the documentation of the JAL compiler. > > Kind regards, > > Rob > > ------------------------------ > *Van:* [email protected] <[email protected]> namens majid > ebru <[email protected]> > *Verzonden:* vrijdag 23 april 2021 19:47 > *Aan:* jallib <[email protected]> > *Onderwerp:* Re: NT: [jallib] How to send & receive data over medium > distance > > > Please help me > > I almost work with micro ,12 years ago . > > Now I can't send / receive data?! > > I should send and receive an integer(like adv value and ....) , but in > serial_sw_data I just can send a byte ?!?!!! > And just read a byte with serial_sw_read(char)?! > > I know that my kowlage about electronic is wake , but now I should do > read&write data?! > > Please guide me,🙏🙏🙏🙏🙏🙏🙏🙏 > > On Thursday, April 22, 2021 at 11:23:23 PM UTC+4:30 [email protected] > wrote: > > Hi Majid, > > You have to provide more information. How do you know that they stopped? > Did you narrow down the code down to the minimal size to show that it > fails? If so you can share that code. > > And to answer your other - not posted - comment. Due to the fact that you > use this group to answer trivial questions that you can find on the > Internet (which you should not do) and which are specific JAL or PIC > related, your posts are now moderated. Only posts which are relevant to > this group are passed on to the other group members. > > Kind regards, > > Rob > > ------------------------------ > *Van:* [email protected] <[email protected]> namens majid > ebru <[email protected]> > *Verzonden:* donderdag 22 april 2021 20:19 > > *Aan:* jallib <[email protected]> > *Onderwerp:* Re: NT: [jallib] How to send & receive data over medium > distance > Hi > > Please help me again😢😢😫😫🥺🥺🤔🤔 > > When I connected two PICs together , everything is ok. > > But when disconnect port serial , both PICs hanged ?!?! > > Both micro stoped , and when connected again ,both micro work correctly?! > > In fact both micro stopped in line : if serial_sw_read(char)) then block > .... > > And doesn't run other codes🤔🥺😫😢 > > Why?! > > How should I do ?! > On Wednesday, April 21, 2021 at 10:12:03 PM UTC+4:30 funlw65(Vasi) wrote: > > The microcontroller boards that are used in Polish Universities are all > equipped with (external - note for Majid) RS485 chips. > > On Wed, Apr 21, 2021 at 4:54 PM Rob CJ <[email protected]> wrote: > > Hi Majid, > > Please use Google to find out what RS485 and IIC is. Use the Jallib group > for issues with libraries and the compiler not for general questions that > you can easily find on the internet. > > Thanks. > > Kind regards, > > Rob > > ------------------------------ > *Van:* [email protected] <[email protected]> namens majid > ebru <[email protected]> > *Verzonden:* woensdag 21 april 2021 15:47 > *Aan:* jallib <[email protected]> > *Onderwerp:* Re: NT: [jallib] How to send & receive data over medium > distance > > RS485 is very powerful. > > But I don't how to implement in PIC?!? > > Is i2c the same rs485?! > > On Wednesday, April 21, 2021 at 4:41:19 PM UTC+4:30 vasile wrote: > > At 15m and 5V there is no problem with data sent in current. Using twisted > wire cable is a good habit. > From the EMI perspective twisted cable it is about half as good as a > shielded cable and has the parasitic capacity quite low compared with the > shielded cable. > RS485 (standard 32 loads) is feasible at 1Km and quite high speed. Still > there is an issue with the ground line and requires good terminators. > Data goes either on A&B plus ground cable (three wires between Tx and RX) > or just A&B (two wire cable) and ground connected to earth on the > transmitter and receiver end. > In the last configuration an issue is quite frequent caused by an offset > (variable ground potential between TX and RX). > Also lightning is a problem for outdoor cables...and nothing help... :)... > no matter how others will convince you to put three tranzorbs on each TX > and RX end. > happy communications! > > > On Wed, Apr 21, 2021 at 8:32 AM 'Oliver Seitz' via jallib < > [email protected]> wrote: > > Thanks for the additional information, 800m is something very different > from 20m ;-) > > I can imagine that 20m at 5V ground-referenced is doable, but when you're > starting, better stick to the specifications and try your luck when you > have a bit of experience. > > I myself am at a similar project, like 15 meter, and I want to use as > little standby current as possible, and no twisted pairs. It's > uni-directional, with constant-current pullup at the receiver and optically > isolated pulldown at the sender with 1200 baud... First test of the concept > in a few days ;-) > > If standby current was of no concern, I'd use RS422 or RS485 > drivers/receivers, true RS232 is old-fashioned and needs to many components. > > > Greets, > Kiste > > Am Mittwoch, 21. April 2021, 07:02:46 MESZ hat vsurducan < > [email protected]> Folgendes geschrieben: > > > > > > Oliver, I remember the problems I had with an EIA232 with +/-8V output > running at 800m at 9600bps. Everything works until due the transceiver > heating the voltage dropped at +/-7.6V...:) > The length is given by the voltage at the level converter of the > transmitter output. All level converters with charge pumps are not able to > give more than +/-8V...+/-10V in the happiest circumstances. > Oldest/goldest EIA232 worked at +/-25V up to 2km. > For 20m you do noy need any level converter at the output of your PIC, > just a twisted pair RX-GND TX-GND (CAT5 ethernet cable is perfect) and an > open collector transmitter ( a gate) with pull-up resistor in the receiver > end (at 20m distance from the transmitter). > However Majid, I think you need first to learn jal and for that there is > a learning curve which has to be passed.... > Please start with the examples, compile them, make them run, modify them > as you wish and post only when nothing works for you after three days of > trying...this will help you more than you may believe right now... > best wishes > > On Wed, Apr 21, 2021 at 7:28 AM 'Oliver Seitz' via jallib < > [email protected]> wrote: > > Hi Majid, > > > > SPI is designed for centimeters, I don't think it can work reliably over > 20 meters. > > > > RS232 at 9600 baud is ok for 150 meters, if you're using real RS232 > drivers and receivers like from the MAX232 series. The PIC controller does > not have RS232, it has a usart which handles the NRZ protocol. This > protocol is best known as being used by the RS232 interface. Therefore the > protocol itself is commonly (but wrongly) referred to as "RS232" > > > > RS232 uses negative voltages as a symbolic "1" and positive voltages for > "0". At the receiving side, the voltage must at least go higher than +3V > for "0" and lower than -3V for "1". At the sending side, voltages from up > to +15V and down to -15V are used. > > > > So, to answer your question in two simple sentences: RS232 is ok for the > job. But RS232 is not what comes out of the controller. > > > > Greets, > > Kiste > > > > > > > > > > Am Dienstag, 20. April 2021, 21:56:34 MESZ hat majid ebru < > [email protected]> Folgendes geschrieben: > > > > > > > > > > > > can i ask another question?? > > > > if it is 20 meter distance between PICs , i should use RS232 or SPI? > > > > so sorry and thanks a lot > > > > majid ebru در تاریخ سهشنبه ۲۰ آوریل ۲۰۲۱ ساعت > > > > -- > > You received this message because you are subscribed to the Google > Groups "jallib" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to [email protected]. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/jallib/1697687282.4677348.1618979276333%40mail.yahoo.com > . > > > > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/jallib/CAM%2Bj4qtaBjojssk_HHFK1M2dhhL9CNNf3mygd1F3nH0B5bck9A%40mail.gmail.com > . > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/jallib/1020737915.4719521.1618983169979%40mail.yahoo.com > . > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/jallib/22c899b2-b475-404d-9982-fb4e9ffe3169n%40googlegroups.com > <https://groups.google.com/d/msgid/jallib/22c899b2-b475-404d-9982-fb4e9ffe3169n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/jallib/AM0PR07MB624188EEE1255C4E45C31F80E6479%40AM0PR07MB6241.eurprd07.prod.outlook.com > <https://groups.google.com/d/msgid/jallib/AM0PR07MB624188EEE1255C4E45C31F80E6479%40AM0PR07MB6241.eurprd07.prod.outlook.com?utm_medium=email&utm_source=footer> > . > > > > -- > Vasi > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/jallib/ad446bf9-5eab-4168-8326-b33f2a02c0f5n%40googlegroups.com > <https://groups.google.com/d/msgid/jallib/ad446bf9-5eab-4168-8326-b33f2a02c0f5n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/jallib/187dbbf2-8c1b-43c2-ac9b-ce320495f60fn%40googlegroups.com > <https://groups.google.com/d/msgid/jallib/187dbbf2-8c1b-43c2-ac9b-ce320495f60fn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/jallib/AM0PR07MB6241CB67E4CBAE8CFD01D0D0E6449%40AM0PR07MB6241.eurprd07.prod.outlook.com > <https://groups.google.com/d/msgid/jallib/AM0PR07MB6241CB67E4CBAE8CFD01D0D0E6449%40AM0PR07MB6241.eurprd07.prod.outlook.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "jallib" group. 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