Post by thread:[PICLIST] [PIC] Check my checklist? :)

You may have guessed, I'm not very patient, so I've already drawn up a checklist / shopping list for my introduction to PIC / electronics. If someone would just check this list briefly it would be very much appreciated; I don't want to be put off by spending a chunk of money on worthless equipment! Here goes.. * PIC book - http://www.sq-1.com/eptoc.html * multimeter - RadioShack.com 22-218 * AD-102 Breadboard - http://www.maplin.co.uk code AG10L * equipment wire - http://www.maplin.co.uk codes FA26D black, FA33L red * newfound warp-13 pic programmer - http://www.dontronics.com/netfound.html * power supply PSU205 - www.quasarelectronics.com/accessories.htm (for warp-13) * PIC6F877 from microchip.com (PDIP package, for breadboard) * AA x 3 battety holder (YR61R) (w/3 AA batteries!) from Maplin.co.uk * Some oscillating dilithium crystal resonating warp drive ceramic kettle thing (could someone help me out? I want something suitable for the OSC pins of the PIC6F877 to make it run at 20Mhz!.. what should it be?) and then for some flashy LED effects: * 3x 470-ohm resistors (for control unit LEDs) * 3x LEDs (for control unit) Jameco.com part # 175679 Well, thats it, thanks again everyone! You've been extremely helpful so far! -Kieren -- 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

Kieren wrote... >You may have guessed, I'm not very patient, so I've already drawn up a >checklist / shopping list for my introduction to PIC / electronics. If >someone would just check this list briefly it would be very much >appreciated; I don't want to be put off by spending a chunk of money on >worthless equipment! > >Here goes.. > >* PIC book - http://www.sq-1.com/eptoc.html >* multimeter - RadioShack.com 22-218 While you're at Radio Shack, also pick up a logic probe. They're handy, especially if you don't have an oscilloscope. They can tell you if the pin you're probing is logic high, logic low, or toggling. >* AD-102 Breadboard - http://www.maplin.co.uk code AG10L >* equipment wire - http://www.maplin.co.uk codes FA26D black, FA33L red (no comment) >* newfound warp-13 pic programmer - http://www.dontronics.com/netfound.html >* power supply PSU205 - www.quasarelectronics.com/accessories.htm >(for warp-13) I'm not familiar with the Warp-13, so I can't comment; but I find Microchip's ICD in-circuit debugger very handy for PIC16F877 work, and I recommend it. A bit pricey, but worth it IMHO. >* PIC6F877 from microchip.com (PDIP package, for breadboard) Buy a couple of them; you might burn out one or two if you're unlucky. OTOH, if you're lucky, you very likely will want a second (and then a third, etc.) in short order anyway because you'll start to get ideas for more projects! Buy a bunch. >* AA x 3 battety holder (YR61R) (w/3 AA batteries!) from Maplin.co.uk There will come a time when you want to operate some PIC gadget from a regulated 5 volt supply. Buy a couple of 7805 voltage regulators; they're cheap. >* Some oscillating dilithium crystal resonating warp drive ceramic kettle >thing (could someone help me out? I want something suitable for the OSC >pins of the PIC6F877 to make it run at 20Mhz!.. what should it be?) Forget the dilithium: too much exposure causes the gonads to shrivel. Also, forget the 20MHz; that's as fast as the chip can go and it may not function at that speed when plugged into one of those breadboard thingies (in my experience, they don't work well at high frequencies, but YMMV). If you really, really need tight frequency control, I'd recommend a lower frequency ceramic resonator, like the ECS, Inc. ZTT-4.00MG (here in the States, they can be had from DigiKey, part number X902-ND). Better yet, just use the PIC's RC oscillator option for your first experiments. It's easier than using crystals or resonators. Some other suggestions: (1) Download the PIC16F877 data sheet from Microchip's web site and read through it. Force yourself to do it, if necessary: it's got loads of important info in it, and it will no doubt prompt lots of questions to which you can get excellent answers here on the PICLIST. (2) Forget the motor/servo stuff for now. For the time being, you're going to be plenty busy just getting an LED to blink on and off. Learn to walk before learning to run, in other words. (3) Get one or more introductory books on electronics. I like Horowitz and Hill's "The Art of Electronics", but others may have their own recommendations. Electronics (at least the basics) is well worth learning if you're going to be working with microcontrollers. Think of it as a "force multiplier" which greatly enhances your overall abilities. Hope this helps a bit... DD -- 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

Thanks for the info! > While you're at Radio Shack, also pick up a logic probe. They're > handy, especially if you don't have an oscilloscope. They can > tell you if the pin you're probing is logic high, logic low, or > toggling. Thanks... I had a look on radioshack.com, did a search, looked under "probes" etc. but cant seem to find a "logic probe"? I'm in the UK and theres no stores near me so I can't go n' ask em :( > > >* AD-102 Breadboard - http://www.maplin.co.uk code AG10L > >* equipment wire - http://www.maplin.co.uk codes FA26D black, FA33L red > > (no comment) Hopefully that's a good no comment? ;) > Better yet, just use the PIC's RC oscillator option for your > first experiments. It's easier than using crystals or > resonators. Interesting, I didnt know it had an internal clock base thingy... I've skimmed the datasheet a couple of times, but as I'm new it takes a while to pick things up. Does it just "detect" theres no crystal/resonator attached and go off by itself? I figure theres gotta be a disadvantage, too.. is it really slow or unstable? (not as that really matters at the moment, though, as you say). Thanks again, Kieren -- 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

Kieren, Be patient! Look around first, especially when buying parts. It is generally better to place either one or two orders from a vendor rather than a bunch of vendors (separate shipping and handling charges). You want to make sure your getting everything you need. Nothing is worse than needing a $1.00 part after already placing an order for everything else. You should visit the the microchip web site and look at some of the application notes. They show how to interface many devices to the PIC series. An absolutely necessary (and free!) document is the full spec sheet for the 16F877 part at: www.microchip.com/download/lit/pline/picmicro/families/16f87x/39582a. pdf Be sure to download and PRINT IT OUT! While it is not aimed at beginners, it can amplify the information in the books from sq-1. From your previous post, it appears that you are just starting out in electronics. You may want to avoid many "stupid" mistakes and hard-to-troubleshoot problems by purchasing either a pre-assembled board or a prototyping board with the traces already laid out for the 16F877 and its 20 MHz osc. Take a look at some of the products at http://www.melabs.com for an example. I'm sort of concerned that you want to run 20 MHz and use a plugboard. You may have oscillator problems and since you don't have the proper equipment to check it, you would never know why your project isn't working correctly (or at all). If you still want to use the plugboard, drop the speed to 4 MHz (and yes, you can use a 20 MHz '877 at 4 MHz). Don't forget to use bypass caps !!! Ken {Original Message removed}

Thanks also for your reply :) > From your previous post, it appears that you are just starting out in > electronics. > You may want to avoid many "stupid" mistakes and hard-to-troubleshoot > problems by purchasing either a pre-assembled board or a prototyping > board with the traces already laid out for the 16F877 and its 20 MHz > osc. Take a look at some of the products at http://www.melabs.com for an > example. I'm sort of concerned that you want to run 20 MHz and use a > plugboard. You may have oscillator problems and since you don't have > the proper equipment to check it, you would never know why your > project isn't working correctly (or at all). If you still want to use the > plugboard, drop the speed to 4 MHz (and yes, you can use a > 20 MHz '877 at 4 MHz). Don't forget to use bypass caps !!! Could someone clarify the problem with using a 20MHz in a solderless breadboard environment? I mean, I cant think of what would be different than a little more resistance from the larger surface area? And whats a bypass cap(acitor)? :) Sorry, asking loads of questions is just how I work ;) -- 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

Kieren, This list is particularly good at answering questions. When you read the documentation from microchip, you will probably have more questions than you started with! Resistance is not the issue with the solderless breadboard, impedance is. At low frequencies, the metal strips "look mostly like" a small resistor, but as frequency goes up, they become a combination of resistance, inductance and capacitance. This causes degradation in any signals that are running through them. For now, just trust me and use a lower frequency. It's more important that you get something that is stable so you can work on other things like using all the great peripherals in the '877 rather than worrying about speed. Flashing LEDs doesn't require 20 MHz. Bypass caps are needed to reduce the spiking on Vcc when digital devices switch state. Microcontrollers have many gates internally and these all create large current spikes on the power supply. Placing bypass caps (with very short leads) between Vcc and Ground supply the needed current during these transitions. If they weren't there, it is possible that your 5 volt supply will spike down to a point where your design either doesn't function, or worse, functions most of the time. Try 0.1uF. If using a protoboard, placing several around the board is also a good idea. Ken {Original Message removed}

Kieren wrote... >Thanks for the info! You're most welcome. >> While you're at Radio Shack, also pick up a logic probe. They're >> handy, especially if you don't have an oscilloscope. They can >> tell you if the pin you're probing is logic high, logic low, or >> toggling. > >Thanks... I had a look on radioshack.com, did a search, looked under >"probes" etc. but cant seem to find a "logic probe"? I'm in the UK and >theres no stores near me so I can't go n' ask em :( Hmmm... when I get to work tomorrow I'll look at my probe and get the RS part number for you. >> >* AD-102 Breadboard - http://www.maplin.co.uk code AG10L >> >* equipment wire - http://www.maplin.co.uk codes FA26D black, FA33L red >> >> (no comment) > >Hopefully that's a good no comment? ;) Actually it was a "I'd probably best not unleash the full force of my hatred for plugboards" kind of "no comment". These boards are OK for some kinds of work, but they have an awful lot of parasitic capacitance (i.e., each of its contact strips exhibits capacitance to the adjacent strips) which can cause some kinds of circuits to function erratically. They can be convenient, I'll admit, but I no longer use them because I got tired of wasting my time chasing down phantom problems caused by parasitics. {Quote hidden}>> Better yet, just use the PIC's RC oscillator option for your >> first experiments. It's easier than using crystals or >> resonators. > >Interesting, I didnt know it had an internal clock base thingy... I've >skimmed the datasheet a couple of times, but as I'm new it takes a while to >pick things up. Does it just "detect" theres no crystal/resonator attached >and go off by itself? I figure theres gotta be a disadvantage, too.. is it >really slow or unstable? (not as that really matters at the moment, though, >as you say). Most of the PICs can be configured to run with any of several oscillator options. These are usually described in the "Special Features of the CPU" section of each PIC's datasheet. For the PIC16F877, there are the LP (Low Power Crystal), XT (medium-speed crystal), HS (high-speed crystal) and RC (Resistor/Capacitor) oscillator modes. In the RC mode, you connect a resistor (anywhere from a few thousand ohms up to a hundred thousand ohms or so) from the Vcc pin to the OSC1 pin, and a capacitor (20 picofarads or more) from the OSC1 pin to ground. The less resistance and capacitance, the faster she goes. The advantage of the RC oscillator mode is low cost: a few pennies for a resistor and a capacitor. The disadvantage of this mode is that the frequency cannot be predicted with any great accuracy. In contrast, a ceramic resonator will usually run within a few tenths of a percent of its marked frequency; and a crystal will be in error by only a few thousandths of a percent. Assuming you're not apt to be doing anything in your first few projects that requires precise timing, the RC oscillator should do nicely. In another post you asked, "what is a bypass capacitor?" A bypass capacitor is a capacitor (commonly in the range of 10nF to 100nF) wired as directly as possible across a chip's power and ground pins. It acts to keep the voltage on the chip's supply pins stable for the brief instants of time during which the chip's logic circuits switch state as it executes code. Most of the current drawn by the chip is drawn during these state changes, and the peak currents can be several hundred milliamperes (that's a LOT of current) for just a few nanoseconds. The reason bypass capacitors are needed is that without them, chips can sometimes "glitch" because those short, sharp current spikes, acting through the unavoidable inductance of your circuit's power wiring, can briefly "drag down" the power supply voltage seen at the chip's Vcc pin(s). And when the voltage gets dragged down enough, the chip malfunctions. What the bypass capacitor does is "hold up" the supply during this brief current spike, rather like a miniature battery. Problems caused by supply voltage glitches are often a nightmare to troubleshoot; so my advice is ALWAYS use bypass capacitors in your circuits, one for each chip connected right across the VCC/GND pins. Hope this helps out a bit... DD -- 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

Hi again everyone :) > This list is particularly good at answering questions. When you > read the documentation from microchip, you will probably > have more questions than you started with! Right! I've printed the PIC16F877 datasheet (all 216 pages, halfway through the cartrdige ran out), and read it as it printed, skipping things like voltage graphs etc., and I think I've got a much better idea now how it all comes together. But I do got some questions for yas :) (1) The "Parallel Port" mode, how does it work? Could I do bidirectional comms with a PC parallel port? What would be a typical application of it? (2) To access file registers in different banks from code, I know you must first set the appropriate STATUS bits, but after that do you refer to the memory location as the absolute address (e.g. 80h and upwards for bank 1) or the relative address, (e.g. specify 0h). I.e. to access byte 0 of page 1 would you do: (a) set page bits to "page 1" then MOVFW 80h or (b) set page bits to "page 1" then MOVFW 0h (3) I don't full understand the program memory paging. Is it all automatic, for example? If you write enough code to fill page 0, will it starting filling page 1, and will all calls/gotos still work between pages (seemlessly)? Or, does it error if you go over the page limit, and you have to ORG 0x900 (or whatever page 1 begins at), and have to BCF/BSF the PCLATH flags every time you goto/call (and what would you do on RETURN?)? (4) PIC-PIC serial comms. Eventually my project will have at least 2 PICs working in unison (one will be using a math coprocessor to do lots of calculations, the other will be the central controller), and I was wondering the easiest way to send messages between them? I reckoned I could attach 2 outputs from the central controller to an input on the other PIC, and 1 (or 2) the other way round. One of the lines could trigger an interrupt on the other one (or at least set an "interrupt occured" flag, so the PIC knows the other one wants to send a message), then the other line would be for serial comms. Could/should I use the inbuilt S2C(I2C?)/UART feature(s) for this, is there an easier/better way? And finally (finally!), what would be the best alternative to breadboard for me to develop higher-frequency circuits on? ~Le fin~ -Kieren -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

To add to my previous post (see below), I would like to know the order code for a PIC16F877 that fits in solderless breadboard (PDIP I think it's called?). I found www.microchip.com/1010/pline/picmicro/category/embctrl/14kbytes/devic es/16f877/options/index.htm, but I'm lost as to which one(s) could work. Thanks again > Hi again everyone :) > > > This list is particularly good at answering questions. When you > > read the documentation from microchip, you will probably > > have more questions than you started with! > > Right! I've printed the PIC16F877 datasheet (all 216 pages, halfway through > the cartrdige ran out), and read it as it printed, skipping things like > voltage graphs etc., and I think I've got a much better idea now how it all > comes together. But I do got some questions for yas :) > > (1) The "Parallel Port" mode, how does it work? Could I do bidirectional > comms with a PC parallel port? What would be a typical application of it? > > (2) To access file registers in different banks from code, I know you must > first set the appropriate STATUS bits, but after that do you refer to the > memory location as the absolute address (e.g. 80h and upwards for bank 1) or > the relative address, (e.g. specify 0h). I.e. to access byte 0 of page 1 > would you do: > (a) set page bits to "page 1" then MOVFW 80h > or > (b) set page bits to "page 1" then MOVFW 0h > > (3) I don't full understand the program memory paging. Is it all automatic, > for example? If you write enough code to fill page 0, will it starting > filling page 1, and will all calls/gotos still work between pages > (seemlessly)? Or, does it error if you go over the page limit, and you have > to ORG 0x900 (or whatever page 1 begins at), and have to BCF/BSF the PCLATH > flags every time you goto/call (and what would you do on RETURN?)? > > (4) PIC-PIC serial comms. Eventually my project will have at least 2 PICs > working in unison (one will be using a math coprocessor to do lots of > calculations, the other will be the central controller), and I was wondering > the easiest way to send messages between them? I reckoned I could attach 2 > outputs from the central controller to an input on the other PIC, and 1 (or > 2) the other way round. One of the lines could trigger an interrupt on the > other one (or at least set an "interrupt occured" flag, so the PIC knows the > other one wants to send a message), then the other line would be for serial > comms. Could/should I use the inbuilt S2C(I2C?)/UART feature(s) for this, > is there an easier/better way? > > And finally (finally!), what would be the best alternative to breadboard for {Quote hidden}> me to develop higher-frequency circuits on? > > ~Le fin~ > > -Kieren > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> You may have guessed, I'm not very patient, so I've already drawn up a > checklist / shopping list for my introduction to PIC / electronics. If > someone would just check this list briefly it would be very much > appreciated; I don't want to be put off by spending a chunk of money on > worthless equipment! Add a few 40-pin *round-pin* ('turned', 'high-quality') IC sockets. Put your PIC in the socket, and plug that assembly into your breadboard. When one of the pins breaks (it will, after some time) you have lost a socket, not a PIC. For an easy start you might take a PIC 16f628: with suitable setting this PIC can run off its internal oscillator, so there is one thing less to worry about. But if you want 20 MHz get a 20 MHz crystal and two 20 or 22 pF capacitors. Check out http://www.voti.nl/wisp628 for first-time blink-a-led test programs (otherwise when nothing seems to work you must also wonder whether your program is wrong, besides worryng about your hardware and your programmer ;) Wouter van Ooijen -- Van Ooijen Technische Informatica: http://www.voti.nl Jal compiler, Wisp programmer, WLoader bootloader, PICs kopen -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body

IS this a job for a pic device or what? It could also be a pulser? Hummmm.... Bill ----- Original Message ----- From: "Dave Dilatush" <.....dilatushKILLspam.....COMCAST.NET> To: <EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU> Sent: Tuesday, July 09, 2002 4:06 AM Subject: Re: [PIC] Check my checklist? :) > Kieren wrote... > > >I had a look on radioshack.com, did a search, looked under > >"probes" etc. but cant seem to find a "logic probe"? I'm in the UK and > >theres no stores near me so I can't go n' ask em :( > > The RS catalog number on mine is 22-303A. I bought it about two > years ago, don't know whether it's still available. > > DD > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listservspam_OUTmitvma.mit.edu with SET PICList DIGEST in the body > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email @spam@listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

>(2) To access file registers in different banks from code, I know you must >first set the appropriate STATUS bits, but after that do you refer to the >memory location as the absolute address (e.g. 80h and upwards for bank 1) or >the relative address, (e.g. specify 0h). I.e. to access byte 0 of page 1 >would you do: > (a) set page bits to "page 1" then MOVFW 80h > or > (b) set page bits to "page 1" then MOVFW 0h > >(3) I don't full understand the program memory paging. Is it all automatic, >for example? If you write enough code to fill page 0, will it starting >filling page 1, and will all calls/gotos still work between pages >(seemlessly)? Or, does it error if you go over the page limit, and you have >to ORG 0x900 (or whatever page 1 begins at), and have to BCF/BSF the PCLATH >flags every time you goto/call (and what would you do on RETURN?)? Well if no-one else has already referred you to it, get the PIC development files from Olin Lathrop's web pages at http://www.embedinc.com/pic/ Check out the example project towards the bottom of this page as well for a good example of how to use these files. The macros contained in this package can make the hassles of dealing with the page and bank switching reduce to a minimum level. They do not stop you ding silly things however :0 >(4) PIC-PIC serial comms. Eventually my project will have at least 2 PICs >working in unison (one will be using a math coprocessor to do lots of >calculations, the other will be the central controller), and I was wondering >the easiest way to send messages between them? I reckoned I could attach 2 >outputs from the central controller to an input on the other PIC, and 1 (or >2) the other way round. One of the lines could trigger an interrupt on the >other one (or at least set an "interrupt occured" flag, so the PIC knows the >other one wants to send a message), then the other line would be for serial >comms. Could/should I use the inbuilt S2C(I2C?)/UART feature(s) for this, >is there an easier/better way? Again check out the Picuart.asm (picuart.zip) file written by Fr. MacGhee which will solve many of the hassles with this particular peripheral. I do not have a current link to this, but someone has probably already pointed you at it. I have a copy of this which I have converted to use Olin's macros, as well as being interrupt driven, and will be releasing to the piclist web site when I am sure it is fully debugged in the system I am building (the uart code does seem to work correctly, but the whole project is not yet debugged). -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads