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. 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