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Discussion Groups | Piclist | Convert / recompile code - 16F84 to 16F628 need help!
A discussion group for the PICMicro microcontroller. Also called the Microchip PIC, this list is dedicated to the use and abuse of this fine, simple, microcontroller. Close to topic posts are welcome, ie. general electronics.
Circuit Board testing - rdowellus - Jan 21 9:42:00 2004
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I am having problems troubleshooting the mainboard on the "Insectronics" project. The 7805 chip is getting very hot and the board does not function so I am sure I have a short. I have double checked all my soldering and it looks and seems to test ok. Looking for basic Circuit Board testing for a beginner. Any suggestions? Circuit Boards for Dummies or something like that? Thank you, |
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Re: Circuit Board testing - Rick C. - Jan 21 10:05:00 2004
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A 7805 that runs somewhat hot may be normal.....to a point of thermal shutdown.
You must calculate how much power your regulator is dissipating and make
adjustments. Either reducing your unregulated voltage, using a bigger heat
sink, bleeding off some heat by a properly selected resistor across the
input and output of the regulator (only if the current does not fluctuate
much), using a heftier regulator, or a switching regulator. Remember: A
TO220 7805, dissipating only one watt will be too hot to touch.
Rick rdowellus wrote: I am having problems troubleshooting the mainboard on |
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Re: Circuit Board testing - Leon Heller - Jan 21 10:13:00 2004
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----- Original Message ----- From: "rdowellus" <> To: <> Sent: Wednesday, January 21, 2004 2:42 PM Subject: [piclist] Circuit Board testing > I am having problems troubleshooting the mainboard on > the "Insectronics" project. The 7805 chip is getting very hot and > the board does not function so I am sure I have a short. I have > double checked all my soldering and it looks and seems to test ok. > Looking for basic Circuit Board testing for a beginner. Any > suggestions? Circuit Boards for Dummies or something like that? I always build a new board up in stages, starting with the regulator. If that is working OK I check all the voltages at the Vcc and Gnd pins of all the other chips. I then add the MCU and crystal and reset circuitry and check if the crystal is oscillating (PICs need to be programmed first). I then put a simple test program in the MCU and make sure that it is working properly before adding the remaining circuitry, testing each function as it is added. Adopting this sort of systematic approach ensures that things go fairly smoothly - it is easy to work out where problems are arising and fix them. In your shoes, if all else fails, I'd isolate the 7805 by cutting the track on the output and see what happens. You can do this with the other stages. It's easy enough to repair the cuts with a piece of wire and some solder. It won't look very pretty when you've finished but you should be able to get it working quite quickly. Leon -- Leon Heller, G1HSM Email: My low-cost Philips LPC210x ARM development system: http://www.geocities.com/leon_heller/lpc2104.html |
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Re: Circuit Board testing - Rick C. - Jan 21 10:29:00 2004
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Also, you do have a 0.1uf capacitor across the input of the regulator and
ground pin, don't you? This is mandatory for the 7800 series. There are
NO exceptions.
Rick rdowellus wrote: I am having problems troubleshooting the mainboard on |
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Re: Circuit Board testing - Phil - Jan 21 11:05:00 2004
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Instead of cutting the trace, try desoldering the 7805 and pulling it out. You might check the resistance between +5 and gnd. Its value depends on your project but if its under 50, you're pulling > 100 mA which is probably too high. If its ok, you try to add 7805 back in while isolating the output so see if its the regulator. I'd check the orientation of the devices, if you haven't already. Its really easy to get confused about which way to read them. Some of them let all their smoke out when wired in backwards and once the smoke is gone, they don't work. Leon is right about building in stages. Get the power right and then move one. Good advice. --- In , "Leon Heller" <leon_heller@h...> wrote: > > ----- Original Message ----- > From: "rdowellus" <rdowellus@y...> > To: <> > Sent: Wednesday, January 21, 2004 2:42 PM > Subject: [piclist] Circuit Board testing > > I am having problems troubleshooting the mainboard on > > the "Insectronics" project. The 7805 chip is getting very hot and > > the board does not function so I am sure I have a short. I have > > double checked all my soldering and it looks and seems to test ok. > > Looking for basic Circuit Board testing for a beginner. Any > > suggestions? Circuit Boards for Dummies or something like that? > > I always build a new board up in stages, starting with the regulator. If > that is working OK I check all the voltages at the Vcc and Gnd pins of all > the other chips. I then add the MCU and crystal and reset circuitry and > check if the crystal is oscillating (PICs need to be programmed first). I > then put a simple test program in the MCU and make sure that it is working > properly before adding the remaining circuitry, testing each function as it > is added. > > Adopting this sort of systematic approach ensures that things go fairly > smoothly - it is easy to work out where problems are arising and fix them. > > In your shoes, if all else fails, I'd isolate the 7805 by cutting the track > on the output and see what happens. You can do this with the other stages. > It's easy enough to repair the cuts with a piece of wire and some solder. It > won't look very pretty when you've finished but you should be able to get it > working quite quickly. > > Leon > -- > Leon Heller, G1HSM > Email: aqzf13@d... > My low-cost Philips LPC210x ARM development system: > http://www.geocities.com/leon_heller/lpc2104.html |
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RE: Circuit Board testing - Shawn McClintock - Jan 21 17:25:00 2004
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#1 - if using a wall transformer, always run the input to the 7805 through at least 1 rectifier diode (halfwave) #2 - Make sure your bypass caps are wired, and if needed, polarized properly. #3 - Get a VOM (Ohm Meter/Voltage Meter) and learn to use it, they are pretty easy. Even an inexpensive one will do you better than nothing. Read up on some basic electronics using the web, many sites have good tips for beginners. You might also try a search for Electronic troubleshooting. Don't be afraid to use the net.. Its your friend (sometimes) Good luck and let us know how you resolve your problem! Shawn -----Original Message----- From: rdowellus [mailto:] Sent: Wednesday, January 21, 2004 8:43 AM To: Subject: [piclist] Circuit Board testing I am having problems troubleshooting the mainboard on the "Insectronics" project. The 7805 chip is getting very hot and the board does not function so I am sure I have a short. I have double checked all my soldering and it looks and seems to test ok. Looking for basic Circuit Board testing for a beginner. Any suggestions? Circuit Boards for Dummies or something like that? Thank you, |
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Convert / recompile code - 16F84 to 16F628 need help! - Shawn McClintock - Jan 21 21:44:00 2004
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I have C source for a project, it was written for the 16F84. I am trying to recompile using Hi-Tec to use the code on a 16F628 so I can add a few routines myself (the code uses most of the 84's mem space) but even after selecting the type of pic to compile for, the resulting HEX file will not work on my 628. I have tried some simple 'blink a LED' sources with same trouble.. 84 blinks, 628 wont. What do I need to do to port my code to a 628? Obviously I am missing something here. Thanks in advance! Shawn |
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Re: Convert / recompile code - 16F84 to 16F628 need help! - Matt Pobursky - Jan 21 23:28:00 2004
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Are you using a Port A bit for your LED drive? Port A on the '628 comes out of reset configured as analog inputs. You need to setup the CMCON register for digital I/O when you initialize Port A. That's one of the common "gotchas" that often comes up when porting software from earlier PICs to the '628. Just a shot in the dark ... Matt Pobursky Maximum Performance Systems On Wed, 21 Jan 2004 20:44:26 -0600, Shawn McClintock wrote: > I have C source for a project, it was written for the 16F84. I am > trying to recompile using Hi-Tec to use the code on a 16F628 so I can > add a few routines myself (the code uses most of the 84's mem space) > but even after selecting the type of pic to compile for, the > resulting HEX file will not work on my 628. I have tried some simple > 'blink a LED' sources with same trouble.. 84 blinks, 628 wont. > > What do I need to do to port my code to a 628? Obviously I am missing > something here. |
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Re: Convert / recompile code - 16F84 to 16F628 need help! - Phil - Jan 22 0:11:00 2004
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maybe you've already done this but have you verified that the 628 hardware works? are you using the same config bits between the 628 and 84? are you using FOSC=RC, by chance? in the 628 there's an additional Fosc bit that's in the same place as one of the CP bits in the 84. When faced with this sort of thing and its got +V, I put a scope probe on the xtal leads to see if its got oscillation. Then I write a tiny little program that toggles an output pin for an LED (er, scope probe). good luck --- In , "Shawn McClintock" <kd6oji@v...> wrote: > I have C source for a project, it was written for the 16F84. I am trying > to recompile using Hi-Tec to use the code on a 16F628 so I can add a few > routines myself (the code uses most of the 84's mem space) but even > after selecting the type of pic to compile for, the resulting HEX file > will not work on my 628. I have tried some simple 'blink a LED' sources > with same trouble.. 84 blinks, 628 wont. > > What do I need to do to port my code to a 628? Obviously I am missing > something here. > > Thanks in advance! > > Shawn |
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RE: Re: Convert / recompile code - 16F84 to 16F628 need help! - Shawn McClintock - Jan 22 7:17:00 2004
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Yes, the hardware is working with the 84. as far as config bits, extosc, no watchdog, etc, I figured the programming software would know the difference and apply correct bit flags. But thanks for the input, I will check into it. Shawn -----Original Message----- From: Phil [mailto:] Sent: Wednesday, January 21, 2004 11:11 PM To: Subject: [piclist] Re: Convert / recompile code - 16F84 to 16F628 need help! maybe you've already done this but have you verified that the 628 hardware works? are you using the same config bits between the 628 and 84? are you using FOSC=RC, by chance? in the 628 there's an additional Fosc bit that's in the same place as one of the CP bits in the 84. When faced with this sort of thing and its got +V, I put a scope probe on the xtal leads to see if its got oscillation. Then I write a tiny little program that toggles an output pin for an LED (er, scope probe). good luck --- In , "Shawn McClintock" <kd6oji@v...> wrote: > I have C source for a project, it was written for the 16F84. I am trying > to recompile using Hi-Tec to use the code on a 16F628 so I can add a few > routines myself (the code uses most of the 84's mem space) but even > after selecting the type of pic to compile for, the resulting HEX file > will not work on my 628. I have tried some simple 'blink a LED' sources > with same trouble.. 84 blinks, 628 wont. > > What do I need to do to port my code to a 628? Obviously I am missing > something here. > > Thanks in advance! > > Shawn to unsubscribe, go to http://www.yahoogroups.com and follow the instructions |
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RE: Convert / recompile code - 16F84 to 16F628 need help! - Shawn McClintock - Jan 22 7:19:00 2004
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I think you found my problem. I am using portA for my LED indicators. I will look and see what I would need to stuff in that register to clear it and run as I/O. Thanks! Shawn -----Original Message----- From: Matt Pobursky [mailto:] Sent: Wednesday, January 21, 2004 10:29 PM To: Subject: Re: [piclist] Convert / recompile code - 16F84 to 16F628 need help! Are you using a Port A bit for your LED drive? Port A on the '628 comes out of reset configured as analog inputs. You need to setup the CMCON register for digital I/O when you initialize Port A. That's one of the common "gotchas" that often comes up when porting software from earlier PICs to the '628. Just a shot in the dark ... Matt Pobursky Maximum Performance Systems On Wed, 21 Jan 2004 20:44:26 -0600, Shawn McClintock wrote: > I have C source for a project, it was written for the 16F84. I am > trying to recompile using Hi-Tec to use the code on a 16F628 so I can > add a few routines myself (the code uses most of the 84's mem space) > but even after selecting the type of pic to compile for, the > resulting HEX file will not work on my 628. I have tried some simple > 'blink a LED' sources with same trouble.. 84 blinks, 628 wont. > > What do I need to do to port my code to a 628? Obviously I am missing > something here. to unsubscribe, go to http://www.yahoogroups.com and follow the instructions |
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Re: Re: Circuit Board testing - Kees Stenekes - Jan 22 10:48:00 2004
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With normal use (i.e. a PIC), a 7805 should not get hotter than 'just touchable'. If you can bake an egg on it, there's a shortcircuit on your 7805-output. It happend to me a few times, and if you're fast enough to disconnect, there's nothing wrong. Otherwise your 7805 is fried... Kees Stenekes --- Phil <> wrote: > Instead of cutting the trace, try desoldering the > 7805 and pulling it > out. You might check the resistance between +5 and > gnd. Its value > depends on your project but if its under 50, you're > pulling > 100 mA > which is probably too high. If its ok, you try to > add 7805 back in > while isolating the output so see if its the > regulator. > > I'd check the orientation of the devices, if you > haven't already. > Its really easy to get confused about which way to > read them. Some > of them let all their smoke out when wired in > backwards and once the > smoke is gone, they don't work. > > Leon is right about building in stages. Get the > power right and then > move one. Good advice. > > --- In , "Leon Heller" > <leon_heller@h...> > wrote: > > > > ----- Original Message ----- > > From: "rdowellus" <rdowellus@y...> > > To: <> > > Sent: Wednesday, January 21, 2004 2:42 PM > > Subject: [piclist] Circuit Board testing > > > > > > > I am having problems troubleshooting the > mainboard on > > > the "Insectronics" project. The 7805 chip is > getting very hot and > > > the board does not function so I am sure I have > a short. I have > > > double checked all my soldering and it looks and > seems to test ok. > > > Looking for basic Circuit Board testing for a > beginner. Any > > > suggestions? Circuit Boards for Dummies or > something like that? > > > > I always build a new board up in stages, starting > with the > regulator. If > > that is working OK I check all the voltages at the > Vcc and Gnd pins > of all > > the other chips. I then add the MCU and crystal > and reset circuitry > and > > check if the crystal is oscillating (PICs need to > be programmed > first). I > > then put a simple test program in the MCU and make > sure that it is > working > > properly before adding the remaining circuitry, > testing each > function as it > > is added. > > > > Adopting this sort of systematic approach ensures > that things go > fairly > > smoothly - it is easy to work out where problems > are arising and > fix them. > > > > In your shoes, if all else fails, I'd isolate the > 7805 by cutting > the track > > on the output and see what happens. You can do > this with the other > stages. > > It's easy enough to repair the cuts with a piece > of wire and some > solder. It > > won't look very pretty when you've finished but > you should be able > to get it > > working quite quickly. > > > > Leon > > -- > > Leon Heller, G1HSM > > Email: aqzf13@d... > > My low-cost Philips LPC210x ARM development > system: > > http://www.geocities.com/leon_heller/lpc2104.html __________________________________ |
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Re: Re: Circuit Board testing - Bert Drake - Jan 22 11:15:00 2004
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I've also had this happen with a blown/bad PIC
chip.
In one circuit, I had an apparently defective 16F877
that was overheating the 7805.
Switching to a new 877 solved the problem
immediately.
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Re: Circuit Board testing - mr_gees100_peas - Jan 22 11:20:00 2004
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--- In , "rdowellus" <rdowellus@y...> wrote: > I am having problems troubleshooting the mainboard on > the "Insectronics" project. The 7805 chip is getting very hot and > the board does not function so I am sure I have a short. I have > double checked all my soldering and it looks and seems to test ok. > Looking for basic Circuit Board testing for a beginner. Any > suggestions? Circuit Boards for Dummies or something like that? > > Thank you, I like building robots for a hobby. Haven't done a whole lot but I encounter a similar problem as you. The 7805 regulator is rated at 1A max. Its ok to run somewhat hot but not hot to the point where you burn your skin., or not hot so that the regulator shuts down. If its heating up is because its exceding the power rating limit. I.E. the current usagge is closse or above 1A. Usually 1A is enugh to drive a pic and a few other Ic but, once you add a motor this is not enought. The average 1.3-5V dc motor uses .350mA without load. That is if you let it spin freely. Once you put a load on it like a wheel or you put the robot on the floor this number increases.if you have 2 motors then is twice as much. But lets say you are only using one motor and you put it on the floor. You probably consuming .500mA for that one motor plus whatever the circuit is using. You see you are getting close to the 1A max. Now, we are assuming you connected the thing right. So, things to do is get yerself a multimeter. Don't need to spend more than $50. you canget good ones for $30. You also need a breadboard. Ok, make a simple circuit. A LED a resitor, a battery and your 7805 regulator. Connected the same way as your robot circuit. If the thing heats up you are conecting it wrong. Even without the heatsink it should not heat up. If this works you know you have the orientation rigth. Now go back to your circuit and disconect the motors. It should not heat up. If it does then disconnect the output leg from the board. Put your meter in amp measurement mode both in the dial as well as in the wires. Some meters have a special slot or hole for measuring current. Ok, now, put the red lead in the output leg of the 7805. Put the black ead in the circuit. Remember that the output leg of the 7805 is not touching yout circuit. Not conected. Read the display and see how much current you are using. if is close to 1A you need a bette regulator. However, without using motors you need a really big circuit to pull close to 1A. So, if the aboved happend you probably have a short. Another thing you could do is measure voltage between power and gound. you should measure the right voltage. By this Imean 5V, 9V, 12V or whatever you are using. anything lower than that indicates that there is a short somewhere. for example using a 5V regulator you should read something like 4.56 to 5.11V. If you see 3V or less then theres a problem. Wel, unless you use a voltage divider that is. The modular aproach is also good. Disconnect parts of your circuit and test for power. Then keep adding or taking away until you get to the point where the circuit doesn't work because of a drop in voltage. A finla note is did you connect everyting right. One cause of problems is a transitor conection or the way you hooked everything. there should always be a resistor between power and whatever. Never ever a direct conection between power and ground. here is an example. 5v ^ | | resistor -----/\/\/------pic pin | | swith / | | gnd you see if you close the switch the pic sees a 0 but there is also a straigth conectio from power to ground. This creates a short . |
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Re: Convert / recompile code - 16F84 to 16F628 need help! - Dwayne Reid - Jan 22 12:37:00 2004
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At 07:44 PM 1/21/2004, Shawn McClintock wrote: >I have C source for a project, it was written for the 16F84. I am trying >to recompile using Hi-Tec to use the code on a 16F628 so I can add a few >routines myself (the code uses most of the 84's mem space) but even >after selecting the type of pic to compile for, the resulting HEX file >will not work on my 628. I have tried some simple 'blink a LED' sources >with same trouble.. 84 blinks, 628 wont. > >What do I need to do to port my code to a 628? Obviously I am missing >something here. The first order of business is to take a close look at both data sheets. Your initial problem is probably that you are not configuring register CMCON - this causes some of the pins on port RA to be in analog mode. The fix is to write 0x07 to CMCON - this puts the affected pins back to digital mode. Another issue may be RAM bank problems - the 'F84 has a single RAM area that is mapped into both bank 0 & bank 1. That means that you can take shortcuts: you can access a user variable on bank 0 even though bit RP0 is set. You can't do this with the 'F628 - there are 4 RAM banks with a total of 224 bytes of RAM vs 35 bytes of RAM for the 'F84 or 68 bytes of RAM for the 'F84A. Also note that the addresses for accessing and writing data eeprom have changed (different banks as well). Finally, check where your user RAM variables are located: user RAM starts at address 0x0C for the 'F84(a) but at address 0x20 for the 'F628. If the variable addresses are hard-coded, you will have to dig in and fix it. dwayne -- Dwayne Reid <> Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 19 years of Engineering Innovation (1984 - 2003) .-. .-. .-. .-. .-. .-. .-. .-. .-. .- `-' `-' `-' `-' `-' `-' `-' `-' `-' Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. |
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Re: Circuit Board testing - burt0072003 - Jan 25 12:54:00 2004
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--- In , "Shawn McClintock" <kd6oji@v...> wrote: #1 check the input voltage if you are trying to get 5 volts out of 24 volts input, the 7805 will get hot. voltage drop across is too much. #2 use current meter between out put and the circuit by lifting the pin this will tell you how much current is drawn by the circuit. then calculate if it is right. #3 let the circuit run for about 3 to 5 minutes and then check if any other component is unusually hot, that component or the surrounding circuit may be at fault. # resistance check between the 5 volts and the ground doesn't ALWAYS indicate as the active components are involved, such as if you have one of the pic port shorted to ground and if it is an output and if you try to set that high. it maybe sinking or sourcing too much current, resistance measurement will not tell you such a fault. > #1 - if using a wall transformer, always run the input to the 7805 > through at least 1 rectifier diode (halfwave) > #2 - Make sure your bypass caps are wired, and if needed, polarized > properly. > #3 - Get a VOM (Ohm Meter/Voltage Meter) and learn to use it, they are > pretty easy. Even an inexpensive one will do you > better than nothing. > > Read up on some basic electronics using the web, many sites have good > tips for beginners. You might also try a search for > Electronic troubleshooting. Don't be afraid to use the net.. Its your > friend (sometimes) > > Good luck and let us know how you resolve your problem! > > Shawn > -----Original Message----- > From: rdowellus [mailto:rdowellus@y...] > Sent: Wednesday, January 21, 2004 8:43 AM > To: > Subject: [piclist] Circuit Board testing > I am having problems troubleshooting the mainboard on > the "Insectronics" project. The 7805 chip is getting very hot and > the board does not function so I am sure I have a short. I have > double checked all my soldering and it looks and seems to test ok. > Looking for basic Circuit Board testing for a beginner. Any > suggestions? Circuit Boards for Dummies or something like that? > > Thank you, |
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Re: Circuit Board testing - rdowellus - Jan 25 13:49:00 2004
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Got it working (see "Its Alive") Ended up diassembling the entire board. There was a short in the foil on the factory board. A decorative ring that ran around the functional circuitry on the board had bled through in munufacturing and was shorting several zones. I knew something was up when I could not isolate several critical zones. A good lesson and I learned a lot in the process. I suppose I assumed that the factory boards might be tested. I will manually test them prior to assembly in the future. The 7805 is running cool now (9V to 5V) and the PIC is functioning perfectly. Thanks Burt --- In , "burt0072003" <burt007@i...> wrote: > --- In , "Shawn McClintock" <kd6oji@v...> > wrote: > > #1 check the input voltage if you are trying to get 5 volts out of 24 > volts input, the 7805 will get hot. voltage drop across is too much. > #2 use current meter between out put and the circuit by lifting the > pin this will tell you how much current is drawn by the circuit. then > calculate if it is right. > #3 let the circuit run for about 3 to 5 minutes and then check if > any other component is unusually hot, that component or the > surrounding circuit may be at fault. > # resistance check between the 5 volts and the ground doesn't ALWAYS > indicate as the active components are involved, such as if you have > one of the pic port shorted to ground and if it is an output and if > you try to set that high. it maybe sinking or sourcing too much > current, resistance measurement will not tell you such a fault. > > > #1 - if using a wall transformer, always run the input to the 7805 > > through at least 1 rectifier diode (halfwave) > > #2 - Make sure your bypass caps are wired, and if needed, polarized > > properly. > > #3 - Get a VOM (Ohm Meter/Voltage Meter) and learn to use it, they > are > > pretty easy. Even an inexpensive one will do you > > better than nothing. > > > > Read up on some basic electronics using the web, many sites have > good > > tips for beginners. You might also try a search for > > Electronic troubleshooting. Don't be afraid to use the net.. Its > your > > friend (sometimes) > > > > Good luck and let us know how you resolve your problem! > > > > Shawn > > > > > > -----Original Message----- > > From: rdowellus [mailto:rdowellus@y...] > > Sent: Wednesday, January 21, 2004 8:43 AM > > To: > > Subject: [piclist] Circuit Board testing > > > > > > I am having problems troubleshooting the mainboard on > > the "Insectronics" project. The 7805 chip is getting very hot and > > the board does not function so I am sure I have a short. I have > > double checked all my soldering and it looks and seems to test ok. > > Looking for basic Circuit Board testing for a beginner. Any > > suggestions? Circuit Boards for Dummies or something like that? > > > > Thank you, |
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Re: Re: Circuit Board testing - Leon Heller - Jan 25 14:19:00 2004
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----- Original Message ----- From: "rdowellus" <> To: <> Sent: Sunday, January 25, 2004 6:49 PM Subject: [piclist] Re: Circuit Board testing > Got it working (see "Its Alive") > Ended up diassembling the entire board. There was a short in the > foil on the factory board. A decorative ring that ran around the > functional circuitry on the board had bled through in munufacturing > and was shorting several zones. I knew something was up when I could > not isolate several critical zones. A good lesson and I learned a > lot in the process. I suppose I assumed that the factory boards > might be tested. I will manually test them prior to assembly in the > future. The 7805 is running cool now (9V to 5V) and the PIC is > functioning perfectly. You can get boards 'electrically tested' for a small additional charge. They usually check each board against each other. Leon -- Leon Heller, G1HSM Email: My low-cost Philips LPC210x ARM development system: http://www.geocities.com/leon_heller/lpc2104.html |
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