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Hi, Recently i tried to make pic16lf877a work on 3.3V but with no result. The pic is working fine on 5V with 4 or 10 MHZ. But when I use another 3.3V voltage supply it does not work neither using 4 MHZ nor 10MHZ. Is there something I forgot when programming the PIC? Any idea? What a pity Kenderis will not run at 200m race. He is faaast! Thank you all, Nikolaos Trikoupis |
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Pic16lf877a working on 5V but not on 3.3V
Started by ●August 17, 2004
Reply by ●August 17, 20042004-08-17
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--- In , "ntricoup" <ntricoup@y...> wrote: > Hi, > Recently i tried to make pic16lf877a work on 3.3V but with no > result. The pic is working fine on 5V with 4 or 10 MHZ. But when I > use another 3.3V voltage supply it does not work neither using 4 MHZ > nor 10MHZ. Is there something I forgot when programming the PIC? Any > idea? Make sure you aren't using BOR as the device will always be in reset. |
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Reply by ●August 17, 20042004-08-17
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And your OSC must be set for other than HS - section 15.1 of the datasheet. --- In , "Scott Lee" <midl_man@y...> wrote: > --- In , "ntricoup" <ntricoup@y...> wrote: > > Hi, > > Recently i tried to make pic16lf877a work on 3.3V but with no > > result. The pic is working fine on 5V with 4 or 10 MHZ. But when I > > use another 3.3V voltage supply it does not work neither using 4 MHZ > > nor 10MHZ. Is there something I forgot when programming the PIC? Any > > idea? > > Make sure you aren't using BOR as the device will always be in reset. |
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Reply by ●August 18, 20042004-08-18
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However acording to fig.17.2 pag.172 DS39528A it must run at 3.3V at 10MHz and HS is starting above the 4MHz, chapter 14.2 on the same datasheet, table 14.1, 14.2. So, run at 10MHz in XT mode, ehh ? A good reader of the Microchip datasheet will say sometimes "Microchip sucks". Not me, it's definitely very difficult to correct some mistakes or inadvertences by a few guys not well payed...:)) The real problem are the hardware informations offered by the producer in it's datasheet. Small, incomplete and sometimes contradictory. You have to read mounrtains of papers to be sure. And then to test. Vasile http://surducan.netfirms.com On Tue, 17 Aug 2004, rtstofer wrote: > > And your OSC must be set for other than HS - section 15.1 of the > datasheet. > > --- In , "Scott Lee" <midl_man@y...> wrote: > > --- In , "ntricoup" <ntricoup@y...> wrote: > > > Hi, > > > Recently i tried to make pic16lf877a work on 3.3V but with no > > > result. The pic is working fine on 5V with 4 or 10 MHZ. But when > I > > > use another 3.3V voltage supply it does not work neither using 4 > MHZ > > > nor 10MHZ. Is there something I forgot when programming the PIC? > Any > > > idea? > > > > Make sure you aren't using BOR as the device will always be in > reset. > > > to unsubscribe, go to http://www.yahoogroups.com and follow the instructions > Yahoo! Groups Links |
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Reply by ●August 18, 20042004-08-18
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What matters is getting the chip to work. Did changing OSC to something other than HS solve the problem? FWIW, I checked at the Digikey site and all 16LF877 are limited to 4 MHz and SOME, but not all, are identified with a -04 suffix. In spite of the graph, they shouldn't work at 10 MHz regardless of the voltage. Or so it seems... At least that is consistent with the table that indicates OSC must be XT for low voltage operation. --- In , Vasile Surducan <vasile@s...> wrote: > > However acording to fig.17.2 pag.172 DS39528A it must run at 3.3V at 10MHz > and HS is starting above the 4MHz, chapter 14.2 on the same datasheet, > table 14.1, 14.2. So, run at 10MHz in XT mode, ehh ? > > A good reader of the Microchip datasheet will say sometimes "Microchip > sucks". Not me, it's definitely very difficult to correct some mistakes or > inadvertences by a few guys not well payed...:)) The real problem are the > hardware informations offered by the producer in it's datasheet. Small, > incomplete and sometimes contradictory. You have to read mounrtains of > papers to be sure. And then to test. > > Vasile > http://surducan.netfirms.com > > On Tue, 17 Aug 2004, rtstofer wrote: > > > > > And your OSC must be set for other than HS - section 15.1 of the > > datasheet. > > > > --- In , "Scott Lee" <midl_man@y...> wrote: > > > --- In , "ntricoup" <ntricoup@y...> wrote: > > > > Hi, > > > > Recently i tried to make pic16lf877a work on 3.3V but with no > > > > result. The pic is working fine on 5V with 4 or 10 MHZ. But when > > I > > > > use another 3.3V voltage supply it does not work neither using 4 > > MHZ > > > > nor 10MHZ. Is there something I forgot when programming the PIC? > > Any > > > > idea? > > > > > > Make sure you aren't using BOR as the device will always be in > > reset. > > > > > > > > > > to unsubscribe, go to http://www.yahoogroups.com and follow the instructions > > Yahoo! Groups Links > > > > > > > > > > |
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Reply by ●August 18, 20042004-08-18
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I finaly turned off BOR and used a 4 MHZ with XT option. The pic was working making many resets with no reason. Using 10 MHZ the resets were much more. Thanx for the help. I will try to figure out what's wrong with the resets. I don't dare to use a 2V supply ..... ;-) In , "rtstofer" <rstofer@p...> wrote: > > What matters is getting the chip to work. Did changing OSC to > something other than HS solve the problem? > > FWIW, I checked at the Digikey site and all 16LF877 are limited to 4 > MHz and SOME, but not all, are identified with a -04 suffix. In > spite of the graph, they shouldn't work at 10 MHz regardless of the > voltage. Or so it seems... At least that is consistent with the > table that indicates OSC must be XT for low voltage operation. > --- In , Vasile Surducan <vasile@s...> wrote: > > > > However acording to fig.17.2 pag.172 DS39528A it must run at 3.3V > at 10MHz > > and HS is starting above the 4MHz, chapter 14.2 on the same > datasheet, > > table 14.1, 14.2. So, run at 10MHz in XT mode, ehh ? > > > > A good reader of the Microchip datasheet will say > sometimes "Microchip > > sucks". Not me, it's definitely very difficult to correct some > mistakes or > > inadvertences by a few guys not well payed...:)) The real problem > are the > > hardware informations offered by the producer in it's datasheet. > Small, > > incomplete and sometimes contradictory. You have to read > mounrtains of > > papers to be sure. And then to test. > > > > Vasile > > http://surducan.netfirms.com > > > > > > > > On Tue, 17 Aug 2004, rtstofer wrote: > > > > > > > > And your OSC must be set for other than HS - section 15.1 of the > > > datasheet. > > > > > > --- In , "Scott Lee" <midl_man@y...> > wrote: > > > > --- In , "ntricoup" <ntricoup@y...> > wrote: > > > > > Hi, > > > > > Recently i tried to make pic16lf877a work on 3.3V but with no > > > > > result. The pic is working fine on 5V with 4 or 10 MHZ. But > when > > > I > > > > > use another 3.3V voltage supply it does not work neither > using 4 > > > MHZ > > > > > nor 10MHZ. Is there something I forgot when programming the > PIC? > > > Any > > > > > idea? > > > > > > > > Make sure you aren't using BOR as the device will always be in > > > reset. > > > > > > > > > > > > > > > to unsubscribe, go to http://www.yahoogroups.com and follow the > instructions > > > Yahoo! Groups Links > > > > > > > > > > > > > > > |
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Reply by ●August 18, 20042004-08-18
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You are pulling MCLR' high, right? If left floating the system may reset just for entertainment. --- In , "ntricoup" <ntricoup@y...> wrote: > I finaly turned off BOR and used a 4 MHZ with XT option. The pic was > working making many resets with no reason. Using 10 MHZ the resets > were much more. Thanx for the help. I will try to figure out what's > wrong with the resets. I don't dare to use a 2V supply ..... ;-) > > In , "rtstofer" <rstofer@p...> wrote: > > > > What matters is getting the chip to work. Did changing OSC to > > something other than HS solve the problem? > > > > FWIW, I checked at the Digikey site and all 16LF877 are limited to > 4 > > MHz and SOME, but not all, are identified with a -04 suffix. In > > spite of the graph, they shouldn't work at 10 MHz regardless of > the > > voltage. Or so it seems... At least that is consistent with the > > table that indicates OSC must be XT for low voltage operation. > > > > > > --- In , Vasile Surducan <vasile@s...> > wrote: > > > > > > However acording to fig.17.2 pag.172 DS39528A it must run at > 3.3V > > at 10MHz > > > and HS is starting above the 4MHz, chapter 14.2 on the same > > datasheet, > > > table 14.1, 14.2. So, run at 10MHz in XT mode, ehh ? > > > > > > A good reader of the Microchip datasheet will say > > sometimes "Microchip > > > sucks". Not me, it's definitely very difficult to correct some > > mistakes or > > > inadvertences by a few guys not well payed...:)) The real > problem > > are the > > > hardware informations offered by the producer in it's datasheet. > > Small, > > > incomplete and sometimes contradictory. You have to read > > mounrtains of > > > papers to be sure. And then to test. > > > > > > Vasile > > > http://surducan.netfirms.com > > > > > > > > > > > > On Tue, 17 Aug 2004, rtstofer wrote: > > > > > > > > > > > And your OSC must be set for other than HS - section 15.1 of > the > > > > datasheet. > > > > > > > > --- In , "Scott Lee" <midl_man@y...> > > wrote: > > > > > --- In , "ntricoup" <ntricoup@y...> > > wrote: > > > > > > Hi, > > > > > > Recently i tried to make pic16lf877a work on 3.3V but with > no > > > > > > result. The pic is working fine on 5V with 4 or 10 MHZ. > But > > when > > > > I > > > > > > use another 3.3V voltage supply it does not work neither > > using 4 > > > > MHZ > > > > > > nor 10MHZ. Is there something I forgot when programming > the > > PIC? > > > > Any > > > > > > idea? > > > > > > > > > > Make sure you aren't using BOR as the device will always be > in > > > > reset. > > > > > > > > > > > > > > > > > > > > to unsubscribe, go to http://www.yahoogroups.com and follow > the > > instructions > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > > > > > |
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Reply by ●August 23, 20042004-08-23
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I found an interesting behavior of some PIC's using low Q oscillator in XT or HS mode. The problems were biggest with ceramic resonators and only sometime dissapears with crystals. However the amplitude on oscout was too small, near the trigger schmidt input value. When the amplitude falling below the trigger, the PIC resets and then "die". If the amplitude rise above the trigger value, PIC runs ok. These amplitude modifications may determine such crazy behavior. One cure is to use an external oscillator and see what's happent. Of course the other "things" like MCLR pulled somewhere, PWRTE on, BODEN off in 3.3V mode, LVP disabled or if enabled then 10K to gnd on LVP pin, no more than 60C ambient temperature and maybe much more... Vasile On Wed, 18 Aug 2004, rtstofer wrote: > > You are pulling MCLR' high, right? If left floating the system may > reset just for entertainment. > > --- In , "ntricoup" <ntricoup@y...> wrote: > > I finaly turned off BOR and used a 4 MHZ with XT option. The pic > was > > working making many resets with no reason. Using 10 MHZ the resets > > were much more. Thanx for the help. I will try to figure out > what's > > wrong with the resets. I don't dare to use a 2V supply ..... ;-) > > > > > > > > In , "rtstofer" <rstofer@p...> wrote: > > > > > > What matters is getting the chip to work. Did changing OSC to > > > something other than HS solve the problem? > > > > > > FWIW, I checked at the Digikey site and all 16LF877 are limited > to > > 4 > > > MHz and SOME, but not all, are identified with a -04 suffix. In > > > spite of the graph, they shouldn't work at 10 MHz regardless of > > the > > > voltage. Or so it seems... At least that is consistent with > the > > > table that indicates OSC must be XT for low voltage operation. > > > > > > > > > --- In , Vasile Surducan <vasile@s...> > > wrote: > > > > > > > > However acording to fig.17.2 pag.172 DS39528A it must run at > > 3.3V > > > at 10MHz > > > > and HS is starting above the 4MHz, chapter 14.2 on the same > > > datasheet, > > > > table 14.1, 14.2. So, run at 10MHz in XT mode, ehh ? > > > > > > > > A good reader of the Microchip datasheet will say > > > sometimes "Microchip > > > > sucks". Not me, it's definitely very difficult to correct some > > > mistakes or > > > > inadvertences by a few guys not well payed...:)) The real > > problem > > > are the > > > > hardware informations offered by the producer in it's > datasheet. > > > Small, > > > > incomplete and sometimes contradictory. You have to read > > > mounrtains of > > > > papers to be sure. And then to test. > > > > > > > > Vasile > > > > http://surducan.netfirms.com > > > > > > > > > > > > > > > > On Tue, 17 Aug 2004, rtstofer wrote: > > > > > > > > > > > > > > And your OSC must be set for other than HS - section 15.1 of > > the > > > > > datasheet. > > > > > > > > > > --- In , "Scott Lee" <midl_man@y...> > > > wrote: > > > > > > --- In , "ntricoup" <ntricoup@y...> > > > wrote: > > > > > > > Hi, > > > > > > > Recently i tried to make pic16lf877a work on 3.3V but > with > > no > > > > > > > result. The pic is working fine on 5V with 4 or 10 MHZ. > > But > > > when > > > > > I > > > > > > > use another 3.3V voltage supply it does not work neither > > > using 4 > > > > > MHZ > > > > > > > nor 10MHZ. Is there something I forgot when programming > > the > > > PIC? > > > > > Any > > > > > > > idea? > > > > > > > > > > > > Make sure you aren't using BOR as the device will always > be > > in > > > > > reset. > > > > > > > > > > > > > > > > > > > > > > > > > to unsubscribe, go to http://www.yahoogroups.com and follow > > the > > > instructions > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > > > > > > > > > > > > to unsubscribe, go to http://www.yahoogroups.com and follow the instructions > Yahoo! Groups Links |
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