Post by thread:[PICLIST] Strange errors with max232 chip

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'[PICLIST] Strange errors with max232 chip'
2001\12\28@093913 by Kathy Quinlan

Hi all :o) Now before anyone says this is not possible, I am off the morphine, I slept last night, I had regular breaks from the computer, and I can not drink alcohol after having my gall bladder removed, but this happened and I saw it, and if someone wants I can post the MAX 232 chip to them so they can vouch for this fault ;o) (if I do not turn it in to a pet first ;o) Ok I have an AVR 8515 (but any Uc will do this) I connected it up as per the destruction manual (correctly as a new chip fixed the fault) my program is set to receive a byte, and then dump one out back to the PC. nothing happened under hyperterm, but using term95 (from my beloved Norton's commander) in hex mode I found that with every byte I sent, the result was above normal 7 bit hex (infact shifted one bit to the left (^2)) and a byte of 00h followed it. Now correct me if I am wrong the MAX 232 only level shifts and inverts (plus generates the + - 10V) so how can it do this ?? Yes I did remove the AVR and short the TX and RX ttl lines and same problem so it has to be the MAX 232 (it is built on strip board but the tracks and jumpers are less than 2") Any ideas ??? Also anyone know a good hex terminal for win 2k as hyperterm is giving me the S$%TS Regards, Kat. ____________________________________________________________________________ /"\ ASCII Ribbon Campaign | K.A.Q. Electronics \ / - NO HTML/RTF in e-mail | Software and Electronic Engineering X - NO Word docs in e-mail | Perth Western Australia / \ | Ph +61 419 923 731 ____________________________________________________________________________ -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2001\12\28@102900 by David VanHorn

> >Now correct me if I am wrong the MAX 232 only level shifts and inverts (plus >generates the + - 10V) so how can it do this ?? The max232 is ONLY a level shifter, but this assumes that it is a properly working MAX232. You should be able to pop a square wave into it, and scope the output, and they should be the same, with just a tiny time delay. If not, it's time for Widlar Optimization. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2001\12\28@104450 by Thomas C. Sefranek

I'd Guess you have the charge pump clock clocking the "data". If it doesn't offend you I suggest checking the wiring to look for missing ground or an EXTRA ground to a charge cap that is NOT supposed to be there. Kathy Quinlan wrote: {Quote hidden}>Hi all :o) > >Ok I have an AVR 8515 (but any Uc will do this) I connected it up as per the >destruction manual (correctly as a new chip fixed the fault) my program is >set to receive a byte, and then dump one out back to the PC. nothing >happened under hyperterm, but using term95 (from my beloved Norton's >commander) in hex mode I found that with every byte I sent, the result was >above normal 7 bit hex (infact shifted one bit to the left (^2)) and a byte >of 00h followed it. > >Now correct me if I am wrong the MAX 232 only level shifts and inverts (plus >generates the + - 10V) so how can it do this ?? > >Yes I did remove the AVR and short the TX and RX ttl lines and same problem >so it has to be the MAX 232 (it is built on strip board but the tracks and >jumpers are less than 2") > >Any ideas ??? > >Regards, > >Kat. > -- * | __O Thomas C. Sefranek spam_OUTtcsTakeThisOuTcmcorp.com |_-\<,_ Amateur Radio Operator: WA1RHP (*)/ (*) Bicycle mobile on 145.41, 448.625 MHz ARRL Instructor, Technical Specialist, VE Contact. hamradio.cmcorp.com/inventory/Inventory.html http://www.harvardrepeater.org -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2001\12\28@105406 by David VanHorn

Any chance you're whanging the data out pin in the routine that feeds bytes to the uart? That might account for the glitch. It seems suspiciously consistant. That is a lot of time though, a bit-time, at any baud, is a long time to a micro. Do you set up the port once and leave it, or are you re-configuring the DDR ? -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2001\12\28@110345 by Kathy Quinlan

----- Original Message ----- From: "David VanHorn" <.....dvanhornKILLspam@spam@CEDAR.NET> > Any chance you're whanging the data out pin in the routine that feeds bytes > to the uart? > That might account for the glitch. It seems suspiciously consistant. > That is a lot of time though, a bit-time, at any baud, is a long time to a > micro. > > Do you set up the port once and leave it, or are you re-configuring the DDR ? Set it up once and leave it :o) ----- Original Message ----- From: "Thomas C. Sefranek" <tcsKILLspamCMCORP.COM> > I'd Guess you have the charge pump clock clocking the "data". > > If it doesn't offend you I suggest checking the wiring to look for > missing ground or an EXTRA ground to a charge cap that is NOT supposed > to be there. checked that first hon, spent 2 days on this fault :o( but the new chip fixed the fault, so I am guessing it is the old chip :o) Regards, Kat. ____________________________________________________________________________ /"\ ASCII Ribbon Campaign | K.A.Q. Electronics \ / - NO HTML/RTF in e-mail | Software and Electronic Engineering X - NO Word docs in e-mail | Perth Western Australia / \ | Ph +61 419 923 731 ____________________________________________________________________________ ----- Original Message ----- From: "David VanHorn" <.....dvanhornKILLspam.....CEDAR.NET> To: <EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU> Sent: Friday, December 28, 2001 11:55 PM Subject: Re: Strange errors with max232 chip > Any chance you're whanging the data out pin in the routine that feeds bytes > to the uart? > That might account for the glitch. It seems suspiciously consistant. > That is a lot of time though, a bit-time, at any baud, is a long time to a > micro. > > Do you set up the port once and leave it, or are you re-configuring the DDR ? > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2001\12\28@110819 by uter van ooijen & floortje hanneman

did you try to loopback without the max? Wouter van Ooijen Van Ooijen Technische Informatica: http://www.voti.nl Jal compiler for PIC uC's: http://www.voti.nl/jal PICs kopen? http://www.voti.nl/shop -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2001\12\28@111025 by uter van ooijen & floortje hanneman

> The max232 is ONLY a level shifter, but this assumes that it is a properly > working MAX232. PLUS inverter Wouter van Ooijen Van Ooijen Technische Informatica: http://www.voti.nl Jal compiler for PIC uC's: http://www.voti.nl/jal PICs kopen? http://www.voti.nl/shop -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2001\12\28@111234 by David VanHorn

> >checked that first hon, spent 2 days on this fault :o( > >but the new chip fixed the fault, so I am guessing it is the old chip :o) I had a PIO chip (essentially, the same I/O ports as an AVR, but for a 6502 system) that had reversed bit ordering after a lightning hit. This PIO had two ports used as digit strobes for a display, so the display spelled out everything backwards. Bit 0 came out on bit 7's pin, bit 1 on bit 6's pin, and so on, for both ports. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2001\12\28@111609 by David VanHorn

At 12:04 PM 12/28/01 +0100, wouter van ooijen & floortje hanneman wrote: > > The max232 is ONLY a level shifter, but this assumes that it is a properly > > working MAX232. > >PLUS inverter +5 to --12 is a level shift... :) -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2001\12\28@112310 by uter van ooijen & floortje hanneman

> +5 to --12 is a level shift... > :) Yeah, but it does not shift 0v to -17v :( Wouter van Ooijen Van Ooijen Technische Informatica: http://www.voti.nl Jal compiler for PIC uC's: http://www.voti.nl/jal PICs kopen? http://www.voti.nl/shop -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2001\12\28@112725 by uter van ooijen & floortje hanneman

better keep the thread on the list... I assume you are taling about the caps on the max232? any value from 1 to 22 uF will do. But I have the idea that you are trying to do somehing that might be a little beyond your grasp. Wouter van Ooijen Van Ooijen Technische Informatica: http://www.voti.nl Jal compiler for PIC uC's: http://www.voti.nl/jal PICs kopen? http://www.voti.nl/shop {Original Message removed}

2001\12\28@113246 by Herbert Graf

Actually it isn't really an "inverter", since a 1 in RS232 is a negative voltage and a one in TTL/CMOS is a positive voltage, and that is what the MAX232 does, you can't really call it an inverter. TTYL > {Original Message removed}

2001\12\28@124028 by Thomas C. Sefranek

Hon? Hon? Young lady I appreciate the honor you do me! About the fix, Hurrah and a Tiger for you! Happy New Year! Kathy Quinlan wrote: > > >{Original Message removed}

2001\12\28@143138 by myke predko

Hi Kathy, Looking through what you're seeing I think you have left the default Flow Control to "Hardware". "Disconnect" Hyperterminal (it comes up as "Connect" as a matter of course), click on "Properties" and then select the "Connect To" tab and click on "Configure". In the new dialog box that comes up, select "None" for "Flow Control". I think you'll find that by default, "Flow Control" is set to "Hardware". One trick that I always use when setting up RS-232 connections is to short "DSR" to "DTR" and "RTS" to "CTS". This will "fool" the hardware flow control into recognizing that the other device is fat, dumb and ready to communicate. Good luck! myke {Original Message removed}

2001\12\28@200135 by Kathy Quinlan

----- Original Message ----- From: "myke predko" <mykespam_OUTPASSPORT.CA> > Hi Kathy, > > Looking through what you're seeing I think you have left the default Flow > Control to "Hardware". Nope > One trick that I always use when setting up RS-232 connections is to short > "DSR" to "DTR" and "RTS" to "CTS". This will "fool" the hardware flow > control into recognizing that the other device is fat, dumb and ready to > communicate. done in the breakout box. > Good luck! It works as I said with a new chip, I am wondering why I get the errors with the old chip. as it does not seem possible that this chip could produce these errors. Regards, Kat. ____________________________________________________________________________ /"\ ASCII Ribbon Campaign | K.A.Q. Electronics \ / - NO HTML/RTF in e-mail | Software and Electronic Engineering X - NO Word docs in e-mail | Perth Western Australia / \ | Ph +61 419 923 731 ____________________________________________________________________________ -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

2001\12\29@092418 by SM Ling

> It works as I said with a new chip, I am wondering why I get the errors with > the old chip. as it does not seem possible that this chip could produce > these errors. Mostly that the capacitance are under-value. What the values now? and are the two Max232 having the same suffixes? Cheers, Ling SM -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

2001\12\30@012359 by Alexandre Domingos F. Souza

>Hi all :o) Hi =(^.^)= (meow!) >Now before anyone says this is not possible, I am off the morphine, I slept >last night, I had regular breaks from the computer, and I can not drink >alcohol after having my gall bladder removed, but this happened and I saw Hmmm, are you crazy? >it, and if someone wants I can post the MAX 232 chip to them so they can >vouch for this fault ;o) (if I do not turn it in to a pet first ;o) Hmmm, post a chip? in the net? how do you do that? ;o) Maybe transmogrifying the chip? ;oD >Ok I have an AVR 8515 (but any Uc will do this) I connected it up as per the >destruction manual (correctly as a new chip fixed the fault) my program is HUauhauhauhauh >Now correct me if I am wrong the MAX 232 only level shifts and inverts >(plus >generates the + - 10V) so how can it do this ?? Yep! But if the MAX 232 has some error like different voltages generated on rs232 line due fo fauty capacitors (yep, it happened!) or some internal craziness. Have you changed it for another MAX232 (yep, stupid question, but just asking ;o)) or MAX232A (I had some problems with the old MAX232 version, corrected when I used the A version >Also anyone know a good hex terminal for win 2k as hyperterm is giving me >the S$%TS Why use windows 2000? For experimenting on the lab table, I have - an old IBM Thinkpad 350C (anyone has a battery - even broken - for it, pleeeaaaaaaaasseeeeee) - a nice old 386 DX 40 with CGA monitor - the nicest of all - HP 200 LX running Telix, only for comm tests These are so cheap that is better than use your w2k mamooth for lab testing ;o) ---8<---Corte aqui---8<---- Alexandre Souza @spam@taitoKILLspamterra.com.br http://planeta.terra.com.br/lazer/pinball/ ---8<---Corte aqui---8<---- -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

2001\12\30@012409 by Alexandre Domingos F. Souza

>they should be the same, with just a tiny time delay. If not, it's time for >Widlar Optimization. ¿ ---8<---Corte aqui---8<---- Alexandre Souza KILLspamtaitoKILLspamterra.com.br http://planeta.terra.com.br/lazer/pinball/ ---8<---Corte aqui---8<---- -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

2001\12\30@024030 by Kathy Quinlan

----- Original Message ----- From: "Alexandre Domingos F. Souza" <RemoveMEtaitoTakeThisOuTTERRA.COM.BR> Why use windows 2000? For experimenting on the lab table, I have - an old IBM Thinkpad 350C (anyone has a battery - even broken - for it, pleeeaaaaaaaasseeeeee) - a nice old 386 DX 40 with CGA monitor - the nicest of all - HP 200 LX running Telix, only for comm tests These are so cheap that is better than use your w2k mamooth for lab testing ;o) Because I run other software like protel 99SE ;o) (win95 and 98 gave major memory problems with Protel 99SE and winamp running ) Regards, Kat. ____________________________________________________________________________ /"\ ASCII Ribbon Campaign | K.A.Q. Electronics \ / - NO HTML/RTF in e-mail | Software and Electronic Engineering X - NO Word docs in e-mail | Perth Western Australia / \ | Ph +61 419 923 731 ____________________________________________________________________________ -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

2001\12\30@033459 by Alexandre Domingos F. Souza

=(^.^)=, >Because I run other software like protel 99SE ;o) (win95 and 98 gave major >memory problems with Protel 99SE and winamp running ) Interesting, had protel 99 around here, and never saw these errors... ;o) ---8<---Corte aqui---8<---- Alexandre Souza spamBeGonetaitospamBeGoneterra.com.br http://planeta.terra.com.br/lazer/pinball/ ---8<---Corte aqui---8<---- -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

2001\12\30@093500 by Gerhard Fiedler

At 22:40 12/28/2001 +0800, Kathy Quinlan wrote: >Also anyone know a good hex terminal for win 2k as hyperterm is giving me >the S$%TS I just stumbled over this one <http://www.endymion.com/portfolio/software/comlite32.htm>. Never tried it, but it's free and looks like something to try, at least. ge -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

2001\12\30@100604 by bob

Good program but could not download it from that site, but found it here http://www.rtcard.com/comlab32.html Bob {Original Message removed}

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