Post by thread:%LED dot matix dsiplay%

> > Hello, > > I have no experience in design projects what so ever. > > I need to design and bulid an LED dot matrix display. The display is > portable, and will run off a battery. The user has to be able to program > various messages into it. The display will be controlled using a PIC. Any > ideas on how to do such a project. > Any ideas would be greatly appreciated. > Two questions: How big a display? And how big a battery? Believe it or not LED's are power hungry little beasties. That's the primary reason that more LED displays are not battry powered. Large displays may need to drive upwards to an amp of power. No small batteries need apply. One good starting place may be Bob Blick's site and his propeller clock. While the motor part may not be of interest, the LED driver and its associated code might. Check out http://www.bobblick.com. Make sure you read up on multiplexed displays since that's what you'll need. BAJ -- http://www.piclist.com hint: PICList Posts must start with ONE topic: "[PIC]:","[SX]:","[AVR]:" =uP ONLY! "[EE]:","[OT]:" =Other "[BUY]:","[AD]:" =Ads

In the archives are posts about - Interfacing a PC keyboard Multi-character moving signs (control of and power supplies for) Waved wands with messages stored in external RAMs Multiplexing/strobing LEDs and the apparent brightness of them with high-current pulsing Types of batteries and battery maintenance You should also stock up on component datasheets as you'll need to do some power usage calculations Once you've sorted out a system it's basically a question of scale The biggest factor you will probably have is the power source. Because of possible long-term high amperage required some types of battery will be better than others eg lead gel cells, and these have to be looked after carefully. For intermittent use, other rechargeables like NiCd would do. Manufacturers' discharge data will help decide -- http://www.piclist.com hint: PICList Posts must start with ONE topic: "[PIC]:","[SX]:","[AVR]:" =uP ONLY! "[EE]:","[OT]:" =Other "[BUY]:","[AD]:" =Ads

Thanks everyone for the quick reply. I need a matrix that will fit 10-12 characters(I'm thinking a 7x10), is that enough? As for the battery, I need to minimize the power for the longest possible battery life. But for starters I'm not concerned with that yet. I need to figure out the matrix size first, and where i can get it Thanks {Quote hidden}>From: Byron A Jeff <.....byronKILLspam@spam@CC.GATECH.EDU> >Reply-To: pic microcontroller discussion list <PICLISTKILLspamMITVMA.MIT.EDU> >To: .....PICLISTKILLspam.....MITVMA.MIT.EDU >Subject: Re: LED dot matix dsiplay >Date: Mon, 13 Nov 2000 00:10:24 -0500 > > > > > Hello, > > > > I have no experience in design projects what so ever. > > > > I need to design and bulid an LED dot matrix display. The display is > > portable, and will run off a battery. The user has to be able to program > > various messages into it. The display will be controlled using a PIC. >Any > > ideas on how to do such a project. > > Any ideas would be greatly appreciated. > > > >Two questions: How big a display? And how big a battery? Believe it or not >LED's are power hungry little beasties. That's the primary reason that >more LED displays are not battry powered. Large displays may need to >drive upwards to an amp of power. No small batteries need apply. > >One good starting place may be Bob Blick's site and his propeller clock. >While the motor part may not be of interest, the LED driver and its >associated code might. Check out http://www.bobblick.com. > >Make sure you read up on multiplexed displays since that's what you'll >need. > >BAJ > >-- >http://www.piclist.com hint: PICList Posts must start with ONE topic: >"[PIC]:","[SX]:","[AVR]:" =uP ONLY! "[EE]:","[OT]:" =Other "[BUY]:","[AD]:" >=Ads > > > > _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: "[PIC]:","[SX]:","[AVR]:" =uP ONLY! "[EE]:","[OT]:" =Other "[BUY]:","[AD]:" =Ads

Is it possible to find a smaller dot diameter??? {Quote hidden}>From: "M. Adam Davis" <KILLspamadavisKILLspamUBASICS.COM> >Reply-To: pic microcontroller discussion list <RemoveMEPICLISTTakeThisOuTMITVMA.MIT.EDU> >To: spamBeGonePICLISTspamBeGoneMITVMA.MIT.EDU >Subject: Re: [pic] LED dot matix dsiplay >Date: Mon, 13 Nov 2000 12:22:01 -0500 > >The minimum legible display you could use per character is 5x5. Ideally >you would use 5x7 for decent display (no descenders) or larger for a good >display. > >You can fit more characters using a large array. Say you want to fit 12 >characters, with each character as a 5x7 matrix. Your total array size >will be 60x7 leds. You end up having about one chip per 5x7 matrix, >depending on how you drive things. > >If you don't mind doing more processing work, you could use the maxim LED >driver chips. Each chip handles 64 LEDs, so you could use one of these >chips for each row of your display (60x7), using 7 chips to drive a 12 >character LED display is pretty decent as far as parts go. The PCB layout >wouldn't be fun, and such long runs of copper may need to be taken into >consideration with respect to current and resistance and how they will >affect the LED brightness down the line. > >-Adam > >Shahier Razik wrote: > > > > So how can I fit more characters without using a large array??? > > > > >From: Michael Rigby-Jones <TakeThisOuTmrjonesEraseMEspam_OUTNORTELNETWORKS.COM> > > >Reply-To: pic microcontroller discussion list <RemoveMEPICLISTTakeThisOuTMITVMA.MIT.EDU> > > >To: PICLISTEraseME.....MITVMA.MIT.EDU > > >Subject: Re: [pic] LED dot matix dsiplay > > >Date: Mon, 13 Nov 2000 15:37:03 -0000 > > > > > >Standard characters used in e.g. LCD displays use a 5x7 arrangement per > > >character which is about as small as you can get without making some > > >characters illegible. You could maybe get away with 4x5, but that >would be > > >a very chunky looking font! Realisticaly you are only going to fit 2, > > >perhaps even 3 characters into a 7x10 array. > > > > > >Mike > > > > {Original Message removed}

I'm confused by what you mean. when I say '5x7 matrix' I am talking about putting 35 LEDs in 7 rows of 5 LEDs each: * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * You can get leds to a very small diameter, and make a very tiny display. Likewise, you can get leds which actually have several leds inside them and have a large diameter. Depending on the LED size and the spacing you can have a tiny display (5mm (less than 1/4 inch) high per character) to a very large display (300mm (one ft) high per character) or larger or smaller. You can also get a pre-built LED matrix display (like above) so you don't have to wire the entire display yourself. What is it you're trying to do? -Adam Shahier Razik wrote: {Quote hidden}> > Is it possible to find a smaller dot diameter??? > > >From: "M. Adam Davis" <EraseMEadavisUBASICS.COM> > >Reply-To: pic microcontroller discussion list <RemoveMEPICLISTEraseMEEraseMEMITVMA.MIT.EDU> > >To: RemoveMEPICLISTspam_OUTKILLspamMITVMA.MIT.EDU > >Subject: Re: [pic] LED dot matix dsiplay > >Date: Mon, 13 Nov 2000 12:22:01 -0500 > > > >The minimum legible display you could use per character is 5x5. Ideally > >you would use 5x7 for decent display (no descenders) or larger for a good > >display. > > > >You can fit more characters using a large array. Say you want to fit 12 > >characters, with each character as a 5x7 matrix. Your total array size > >will be 60x7 leds. You end up having about one chip per 5x7 matrix, > >depending on how you drive things. > > > >If you don't mind doing more processing work, you could use the maxim LED > >driver chips. Each chip handles 64 LEDs, so you could use one of these > >chips for each row of your display (60x7), using 7 chips to drive a 12 > >character LED display is pretty decent as far as parts go. The PCB layout > >wouldn't be fun, and such long runs of copper may need to be taken into > >consideration with respect to current and resistance and how they will > >affect the LED brightness down the line. > > > >-Adam > > > >Shahier Razik wrote: > > > > > > So how can I fit more characters without using a large array??? > > > > > > >From: Michael Rigby-Jones <RemoveMEmrjonesTakeThisOuTspamNORTELNETWORKS.COM> > > > >Reply-To: pic microcontroller discussion list <EraseMEPICLISTspamspamBeGoneMITVMA.MIT.EDU> > > > >To: RemoveMEPICLISTKILLspamMITVMA.MIT.EDU > > > >Subject: Re: [pic] LED dot matix dsiplay > > > >Date: Mon, 13 Nov 2000 15:37:03 -0000 > > > > > > > >Standard characters used in e.g. LCD displays use a 5x7 arrangement per > > > >character which is about as small as you can get without making some > > > >characters illegible. You could maybe get away with 4x5, but that > >would be > > > >a very chunky looking font! Realisticaly you are only going to fit 2, > > > >perhaps even 3 characters into a 7x10 array. > > > > > > > >Mike > > > > > {Original Message removed}

>> Is it possible to find a smaller dot diameter??? Sure. You can get little dot-matrix LED displays with several characters worth of dots in a package the size of a 14pin DIP or so. The logic content of these vary from not-much-more than LED drivers to drivers and shift registers to full ascii compatibility (including character generators.) On the minus side, these tend to be several 5x7 arrays (separate characters) rather than a single Nx7 matrix. See, for instance, the Agilent HCMS-291x. One of the current projects I have in mind for my spare time is PIC and/or AVR serial-LED style display using some (variable number) of these... Be aware that even with tiny LEDs, any reasonable number of digits ends up consuming quite a LOT of power compared to a PIC or LCD display. BillW -- http://www.piclist.com hint: PICList Posts must start with ONE topic: "[PIC]:","[SX]:","[AVR]:" =uP ONLY! "[EE]:","[OT]:" =Other "[BUY]:","[AD]:" =Ads

> > Thanks everyone for the quick reply. I need a matrix that will fit 10-12 > characters(I'm thinking a 7x10), is that enough? No. Not even enough for a scrolling display. You need to have enough context for someone to read. Think one character per 5x7 matrix. At least 5 characters for scrolling context. So probably 25x7 minimum. > As for the battery, I need to minimize the power for the longest possible > battery life. But for starters I'm not concerned with that yet. You have to be concerned with it. Point blank: LED's suck power. And for brightness they need even more power. Especially when the display is multiplexed. Take the 25x7 example above. If you power a row at a time, you can have up to 25 LED's on at the same time. For adequate brightness, you'll need probably 100ma per LED. Totals out to 2.5A right off the top. Even if you do it one column at a time it'll still be costly. Since the refresh rate will be less than the rows, you'll have to apply even more power to the LEDs to get adequte brightness (150-200ma each). It's still going to be well more than an amp of power to drive them. Batteries and LED's don't mix. Try a simple test: take a 9V battery and drive an LED continously through a 470 ohm resistor (20 ma). See how long it stays on. BAJ > > I need to figure out the matrix size first, and where i can get it As for where you can get matrixes, check out http://www.bgmicro.com and http://www.mpja.com. Both are surplus houses that sell LED matrixes for reasonable prices. BAJ {Quote hidden}> > Thanks > > >From: Byron A Jeff <byronSTOPspamspam_OUTCC.GATECH.EDU> > >Reply-To: pic microcontroller discussion list <spamBeGonePICLISTSTOPspamEraseMEMITVMA.MIT.EDU> > >To: KILLspamPICLISTspamBeGoneMITVMA.MIT.EDU > >Subject: Re: LED dot matix dsiplay > >Date: Mon, 13 Nov 2000 00:10:24 -0500 > > > > > > > > Hello, > > > > > > I have no experience in design projects what so ever. > > > > > > I need to design and bulid an LED dot matrix display. The display is > > > portable, and will run off a battery. The user has to be able to program > > > various messages into it. The display will be controlled using a PIC. > >Any > > > ideas on how to do such a project. > > > Any ideas would be greatly appreciated. > > > > > > >Two questions: How big a display? And how big a battery? Believe it or not > >LED's are power hungry little beasties. That's the primary reason that > >more LED displays are not battry powered. Large displays may need to > >drive upwards to an amp of power. No small batteries need apply. > > > >One good starting place may be Bob Blick's site and his propeller clock. > >While the motor part may not be of interest, the LED driver and its > >associated code might. Check out http://www.bobblick.com. > > > >Make sure you read up on multiplexed displays since that's what you'll > >need. > > > >BAJ > > > >-- > >http://www.piclist.com hint: PICList Posts must start with ONE topic: > >"[PIC]:","[SX]:","[AVR]:" =uP ONLY! "[EE]:","[OT]:" =Other "[BUY]:","[AD]:" > >=Ads > > > > > > > > > > _________________________________________________________________________ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. > > Share information about yourself, create your own public profile at > http://profiles.msn.com. > > -- > 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

Thanks eveeryone. Basically I need to make the final product about the size of a badage. I have to be able to attach it to a bag, or a vest, or even the back of bike. It has to be portable. Thanks {Quote hidden}>From: "M. Adam Davis" <spamBeGoneadavisKILLspamUBASICS.COM> >Reply-To: pic microcontroller discussion list <.....PICLISTspam_OUTMITVMA.MIT.EDU> >To: TakeThisOuTPICLIST.....TakeThisOuTMITVMA.MIT.EDU >Subject: Re: [pic] LED dot matix dsiplay >Date: Mon, 13 Nov 2000 12:59:16 -0500 > >I'm confused by what you mean. when I say '5x7 matrix' I am talking about >putting 35 LEDs in 7 rows of 5 LEDs each: >* * * * * >* * * * * >* * * * * >* * * * * >* * * * * >* * * * * >* * * * * > >You can get leds to a very small diameter, and make a very tiny display. >Likewise, you can get leds which actually have several leds inside them >and have a large diameter. Depending on the LED size and the spacing you >can have a tiny display (5mm (less than 1/4 inch) high per character) to a >very large display (300mm (one ft) high per character) or larger or >smaller. > >You can also get a pre-built LED matrix display (like above) so you don't >have to wire the entire display yourself. > >What is it you're trying to do? > >-Adam > >Shahier Razik wrote: > > > > Is it possible to find a smaller dot diameter??? > > > > >From: "M. Adam Davis" <TakeThisOuTadavisKILLspamspamUBASICS.COM> > > >Reply-To: pic microcontroller discussion list <.....PICLISTRemoveMEMITVMA.MIT.EDU> > > >To: RemoveMEPICLISTspamBeGoneMITVMA.MIT.EDU > > >Subject: Re: [pic] LED dot matix dsiplay > > >Date: Mon, 13 Nov 2000 12:22:01 -0500 > > > > > >The minimum legible display you could use per character is 5x5. >Ideally > > >you would use 5x7 for decent display (no descenders) or larger for a >good > > >display. > > > > > >You can fit more characters using a large array. Say you want to fit >12 > > >characters, with each character as a 5x7 matrix. Your total array size > > >will be 60x7 leds. You end up having about one chip per 5x7 matrix, > > >depending on how you drive things. > > > > > >If you don't mind doing more processing work, you could use the maxim >LED > > >driver chips. Each chip handles 64 LEDs, so you could use one of these > > >chips for each row of your display (60x7), using 7 chips to drive a 12 > > >character LED display is pretty decent as far as parts go. The PCB >layout > > >wouldn't be fun, and such long runs of copper may need to be taken into > > >consideration with respect to current and resistance and how they will > > >affect the LED brightness down the line. > > > > > >-Adam > > > > > >Shahier Razik wrote: > > > > > > > > So how can I fit more characters without using a large array??? > > > > > > > > >From: Michael Rigby-Jones <spamBeGonemrjones@spam@spam_OUTNORTELNETWORKS.COM> > > > > >Reply-To: pic microcontroller discussion list ><TakeThisOuTPICLISTspamMITVMA.MIT.EDU> > > > > >To: PICLISTEraseMEMITVMA.MIT.EDU > > > > >Subject: Re: [pic] LED dot matix dsiplay > > > > >Date: Mon, 13 Nov 2000 15:37:03 -0000 > > > > > > > > > >Standard characters used in e.g. LCD displays use a 5x7 arrangement >per > > > > >character which is about as small as you can get without making >some > > > > >characters illegible. You could maybe get away with 4x5, but that > > >would be > > > > >a very chunky looking font! Realisticaly you are only going to fit >2, > > > > >perhaps even 3 characters into a 7x10 array. > > > > > > > > > >Mike > > > > > > {Original Message removed}

Thanks for those parts BOb. Could it be programmed using a PIC {Quote hidden}>From: Bob Ammerman <RemoveMERAMMERMANEraseMEspam_OUTPRODIGY.NET> >Reply-To: pic microcontroller discussion list <@spam@PICLISTRemoveMEEraseMEMITVMA.MIT.EDU> >To: EraseMEPICLIST@spam@MITVMA.MIT.EDU >Subject: Re: [pic] LED dot matix dsiplay >Date: Mon, 13 Nov 2000 20:56:37 -0500 > >At http://www.bgmicro.com > >Part # LEDPD2435 - red, 4 character, 5x7 _small_ LED display, ASCII driven > >Part # LEDPD2437 - green, 4 character, 5x7 _small_ LED display, ASCII >driven > >Datasheet: > >http://www.bgmicro.com/pdf/pd24xx.pdf > > >Bob Ammerman >RAm Systems >(contract development of high performance, high function, low-level >software) > >-- >http://www.piclist.com hint: PICList Posts must start with ONE topic: >[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

> At http://www.bgmicro.com > > Part # LEDPD2435 - red, 4 character, 5x7 _small_ LED display, ASCII driven > > Part # LEDPD2437 - green, 4 character, 5x7 _small_ LED display, ASCII driven > > Datasheet: > > http://www.bgmicro.com/pdf/pd24xx.pdf > A little more detail: Variable brightness under program control: off, low, medium, high $3.99 per 4 digit module. These displays are 1" x .7" and contain 4 characters, on .25" centers. Each character is 5x7 dots and .2" tall. Pins are on 0.1" centers. They can be stacked end to end to make any multiple of 4 characters. Full upper and lower-case ascii. Lamp test lights all 5x7x4 = 140 LEDs to 1/2 brightness @ about 42ma. Normal operation at full brightness with 20 LEDs on in each character draws about 140ma. Straightforward interfacing will require 13 pins for the first 4 character device, and one additional pin for each additional 4 characters. Bob Ammerman RAm Systems (contract development of high performance, high function, low-level software) {Quote hidden}> > Bob Ammerman > RAm Systems > (contract development of high performance, high function, low-level > software) > > -- > 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

> Any ideas where I can find some helpful information (sample programs) on > programming LED displays uisng pic's Although I am sure there are samples for driving conventional multiplexed LED displays, these displays are nothing like that. In fact, from a programming point of view, these are much closer to an LCD display. Here is a little bit to get you started: Assume you are using a 28 pin PIC. That'll give you enough I/O pins. Assume we are using 4 4-digit displays. Tie /RD high on all 4 LED devices Connect CLK IO on all 4 devices together Tie CLKSEL high on the first device, low on all the others Tie all the RST's together and then to PORT A0 of the PIC. Tie CE0 low on all 4 devices. Connect PORT C to the data pins on all 4 LED devices. Connect RB0 to to A0, RB1 to A1, RB2 to A2, RB3 to /WR on all 4 LED devices. Connect RB4 to to CE1 on one device, RB5 to CE1 on a second device, RB6 to CE1 on a third device, RB7 to CE1 on a fourth device. Initialize PORT C to all outputs, with a value of 0. Initialize PORT B to all outputs, with a value of B'00001000'. Initialize PORT A bit 0 to be an output, with a value of B'0' After powerup: bsf PORTA,0 ; Allow LED devices to come out of reset ; The following code will clear all four devices, then write 'ABCD' on the first device, ; (warning, untested code) MOVLW B'11111000' ; /WR is inactive, ;CE1 set on all devices, ;address is 0 MOVWF PORTB MOVLW B'10000011' ; Clear command - full brightness mode MOVWF PORTC BCF PORTB,3 ; Generate /WR pulse (to all devices!) BSF PORTB,3 MOVLW B'10001111' ; /WR is inactive, ; CE1 is set on first device only, ; address is 7 (leftmost digit) MOVLW 'A' MOVWF PORTC BCF PORTB,3 ; Generate /WR pulse BSF PORTB,3 DECF PORTB,F ; Address 6 (2nd character) MOVLW 'B' MOVWF PORTC BCF PORTB,3 ; Generate /WR pulse BSF PORTB,3 DECF PORTB,F ; Address 5 (3rd character) MOVLW 'C' MOVWF PORTC BCF PORTB,3 ; Generate /WR pulse BSF PORTB,3 DECF PORTB,F ; Address 4 (4th character) MOVLW 'D' MOVWF PORTC BCF PORTB,3 ; Generate /WR pulse BSF PORTB,3 hopefully that should be enough to get you started. Bob Ammerman RAm Systems (contract development of high performance, high function, low-level software) -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Thanks Bob for the code. But just a couple of beginner questions: -what do you mean when you say device? -what are the dimensions of the matrix we dealing with here? -what exactly does that code you sent me accomplish? Thank you {Quote hidden}>From: Bob Ammerman <.....RAMMERMANRemoveMEPRODIGY.NET> >Reply-To: pic microcontroller discussion list <.....PICLISTSTOPspam@spam@MITVMA.MIT.EDU> >To: PICLISTEraseME@spam@MITVMA.MIT.EDU >Subject: Re: [pic] LED dot matix dsiplay >Date: Mon, 13 Nov 2000 23:28:26 -0500 > > > Any ideas where I can find some helpful information (sample programs) on > > programming LED displays uisng pic's > >Although I am sure there are samples for driving conventional multiplexed >LED displays, these displays are nothing like that. > >In fact, from a programming point of view, these are much closer to an LCD >display. > >Here is a little bit to get you started: > >Assume you are using a 28 pin PIC. That'll give you enough I/O pins. > >Assume we are using 4 4-digit displays. > >Tie /RD high on all 4 LED devices > >Connect CLK IO on all 4 devices together > >Tie CLKSEL high on the first device, low on all the others > >Tie all the RST's together and then to PORT A0 of the PIC. > >Tie CE0 low on all 4 devices. > >Connect PORT C to the data pins on all 4 LED devices. > >Connect RB0 to to A0, RB1 to A1, RB2 to A2, RB3 to /WR on all 4 LED >devices. > >Connect RB4 to to CE1 on one device, RB5 to CE1 on a second device, RB6 to >CE1 on a third device, RB7 to CE1 on a fourth device. > >Initialize PORT C to all outputs, with a value of 0. > >Initialize PORT B to all outputs, with a value of B'00001000'. > >Initialize PORT A bit 0 to be an output, with a value of B'0' > > >After powerup: > > bsf PORTA,0 ; Allow LED devices to come out of reset > > >; The following code will clear all four devices, then write 'ABCD' on the >first device, > >; (warning, untested code) > > MOVLW B'11111000' ; /WR is inactive, > ;CE1 set on all >devices, > ;address is 0 > MOVWF PORTB > > MOVLW B'10000011' ; Clear command - full brightness mode > MOVWF PORTC > > BCF PORTB,3 ; Generate /WR pulse (to all >devices!) > BSF PORTB,3 > > MOVLW B'10001111' ; /WR is inactive, > ; CE1 is set on first >device only, > ; address is 7 >(leftmost >digit) > > MOVLW 'A' > MOVWF PORTC > > BCF PORTB,3 ; Generate /WR pulse > BSF PORTB,3 > > DECF PORTB,F ; Address 6 (2nd character) > > MOVLW 'B' > MOVWF PORTC > > BCF PORTB,3 ; Generate /WR pulse > BSF PORTB,3 > > DECF PORTB,F ; Address 5 (3rd character) > > MOVLW 'C' > MOVWF PORTC > > BCF PORTB,3 ; Generate /WR pulse > BSF PORTB,3 > > DECF PORTB,F ; Address 4 (4th character) > > MOVLW 'D' > MOVWF PORTC > > BCF PORTB,3 ; Generate /WR pulse > BSF PORTB,3 > > >hopefully that should be enough to get you started. > >Bob Ammerman >RAm Systems >(contract development of high performance, high function, low-level >software) > >-- >http://www.piclist.com hint: PICList Posts must start with ONE topic: >[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. -- 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

----- Original Message ----- From: Shahier Razik <RemoveMEsrazik00spamBeGoneHOTMAIL.COM> To: <spamBeGonePICLISTKILLspam@spam@MITVMA.MIT.EDU> Sent: Tuesday, November 14, 2000 12:22 AM Subject: Re: [pic] LED dot matix dsiplay > Thanks Bob for the code. But just a couple of beginner questions: > > -what do you mean when you say device? Each device is one 'chip' which contains 4 character positions, each of which is a matrix of 5x7 LEDs. > -what are the dimensions of the matrix we dealing with here? Each character's 5x7 matrix is 0.2 inches high. They are placed on 0.25 in centers. The entire device is 1" x 0.7" . > -what exactly does that code you sent me accomplish? As mentioned in the comments: "The following code will clear all four devices, then write 'ABCD' on the first device," Bob Ammerman RAm Systems (contract development of high performance, high function, low-level software) {Quote hidden}> Thank you > >From: Bob Ammerman <RAMMERMANspam_OUT@spam@PRODIGY.NET> > >Reply-To: pic microcontroller discussion list <spamBeGonePICLIST@spam@MITVMA.MIT.EDU> > >To: RemoveMEPICLISTEraseMEKILLspamMITVMA.MIT.EDU > >Subject: Re: [pic] LED dot matix dsiplay > >Date: Mon, 13 Nov 2000 23:28:26 -0500 > > > > > Any ideas where I can find some helpful information (sample programs) on > > > programming LED displays uisng pic's > > > >Although I am sure there are samples for driving conventional multiplexed > >LED displays, these displays are nothing like that. > > > >In fact, from a programming point of view, these are much closer to an LCD {Quote hidden}> >display. > > > >Here is a little bit to get you started: > > > >Assume you are using a 28 pin PIC. That'll give you enough I/O pins. > > > >Assume we are using 4 4-digit displays. > > > >Tie /RD high on all 4 LED devices > > > >Connect CLK IO on all 4 devices together > > > >Tie CLKSEL high on the first device, low on all the others > > > >Tie all the RST's together and then to PORT A0 of the PIC. > > > >Tie CE0 low on all 4 devices. > > > >Connect PORT C to the data pins on all 4 LED devices. > > > >Connect RB0 to to A0, RB1 to A1, RB2 to A2, RB3 to /WR on all 4 LED > >devices. > > > >Connect RB4 to to CE1 on one device, RB5 to CE1 on a second device, RB6 to {Quote hidden}> >CE1 on a third device, RB7 to CE1 on a fourth device. > > > >Initialize PORT C to all outputs, with a value of 0. > > > >Initialize PORT B to all outputs, with a value of B'00001000'. > > > >Initialize PORT A bit 0 to be an output, with a value of B'0' > > > > > >After powerup: > > > > bsf PORTA,0 ; Allow LED devices to come out of reset > > > > > >; The following code will clear all four devices, then write 'ABCD' on the {Quote hidden}> >first device, > > > >; (warning, untested code) > > > > MOVLW B'11111000' ; /WR is inactive, > > ;CE1 set on all > >devices, > > ;address is 0 > > MOVWF PORTB > > > > MOVLW B'10000011' ; Clear command - full brightness mode > > MOVWF PORTC > > > > BCF PORTB,3 ; Generate /WR pulse (to all > >devices!) > > BSF PORTB,3 > > > > MOVLW B'10001111' ; /WR is inactive, > > ; CE1 is set on first {Quote hidden}> >device only, > > ; address is 7 > >(leftmost > >digit) > > > > MOVLW 'A' > > MOVWF PORTC > > > > BCF PORTB,3 ; Generate /WR pulse > > BSF PORTB,3 > > > > DECF PORTB,F ; Address 6 (2nd character) > > > > MOVLW 'B' > > MOVWF PORTC > > > > BCF PORTB,3 ; Generate /WR pulse > > BSF PORTB,3 > > > > DECF PORTB,F ; Address 5 (3rd character) > > > > MOVLW 'C' > > MOVWF PORTC > > > > BCF PORTB,3 ; Generate /WR pulse > > BSF PORTB,3 > > > > DECF PORTB,F ; Address 4 (4th character) > > > > MOVLW 'D' > > MOVWF PORTC > > > > BCF PORTB,3 ; Generate /WR pulse > > BSF PORTB,3 > > > > > >hopefully that should be enough to get you started. > > > >Bob Ammerman > >RAm Systems > >(contract development of high performance, high function, low-level > >software) > > > >-- > >http://www.piclist.com hint: PICList Posts must start with ONE topic: > >[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > > > > _________________________________________________________________________ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. > > Share information about yourself, create your own public profile at > http://profiles.msn.com. > > -- > 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 > > -- 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

BG Micro (http://www.bgmicro.com) has another option. Their ACS1076, which is a HP HDSP-2303. This is also a 4-digit 5x7 dot matrix 0.2" LED display. This one, however, is much smaller. The 14-pin package is the same size as a DIP16. The characters are 0.2" on center, and they are end-to-end stackable. They are supposed to be quite bright (readable in direct sunlight!), but they suck major current (as much as 500ma when fully lit) The price is quite a bit lower: $1.19 for 1-9, $.89 at 10+. These are no where near as smart as the others, however. Basically, they contain a 28 bit shift register to define the current input for the 7 rows of each of the four digits. There are 5 separate column inputs that must be driven in sequence. The basic operation: 1: Load the 28 bit shift register with the pixels for column 1 of each character. 2: Enable the first column driver. 3: Delay 4: Disable the first column driver. repeat steps 1 through 4 for the other 4 columns. go back to step 1. The PIC, in this case must continuously refresh (multiplex) the display. A PWM drive can control the brightness. -- 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

Bob, I checked out part #LEDPD2435 at bgmicro, but there was to preview of the part. Let me get this straight. This part displays 4 characters at one time, every character is 5x7 dots, .2" tall. The part contians 140 LEDs(5x7x4), and it requires one PIC to program it. {Quote hidden}>From: Bob Ammerman <spamBeGoneRAMMERMANspam_OUTRemoveMEPRODIGY.NET> >Reply-To: pic microcontroller discussion list <.....PICLISTRemoveMEMITVMA.MIT.EDU> >To: PICLIST@spam@MITVMA.MIT.EDU >Subject: Re: [pic] LED dot matix dsiplay >Date: Tue, 14 Nov 2000 02:58:01 -0500 > >BG Micro (http://www.bgmicro.com) has another option. Their ACS1076, which is a HP >HDSP-2303. > >This is also a 4-digit 5x7 dot matrix 0.2" LED display. This one, however, >is much smaller. The 14-pin package is the same size as a DIP16. The >characters are 0.2" on center, and they are end-to-end stackable. > >They are supposed to be quite bright (readable in direct sunlight!), but >they suck major current (as much as 500ma when fully lit) > >The price is quite a bit lower: $1.19 for 1-9, $.89 at 10+. > >These are no where near as smart as the others, however. > >Basically, they contain a 28 bit shift register to define the current input >for the 7 rows of each of the four digits. There are 5 separate column >inputs that must be driven in sequence. > >The basic operation: > >1: Load the 28 bit shift register with the pixels for column 1 of each >character. > >2: Enable the first column driver. > >3: Delay > >4: Disable the first column driver. > >repeat steps 1 through 4 for the other 4 columns. > >go back to step 1. > >The PIC, in this case must continuously refresh (multiplex) the display. > >A PWM drive can control the brightness. > >-- >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 > > _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. -- 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

----- Original Message ----- From: Shahier Razik <EraseMEsrazik00RemoveMESTOPspamHOTMAIL.COM> To: <RemoveMEPICLISTKILLspamTakeThisOuTMITVMA.MIT.EDU> Sent: Tuesday, November 14, 2000 11:24 AM Subject: Re: [pic] LED dot matix dsiplay > Bob, > > I checked out part #LEDPD2435 at bgmicro, but there was to preview of the > part. Let me get this straight. This part displays 4 characters at one time, > every character is 5x7 dots, .2" tall. The part contians 140 LEDs(5x7x4), > and it requires one PIC to program it. Yes, yes, yes, yes, and yes. The datasheet for this part is at: http://ww.bgmicro.com/pdf/pd24xx.pdf You can get a datasheet for the the other part (the smaller but dumber one) at: http://www.bgmicro.com/pdf/acs1076.pdf Bob Ammerman RAm Systems (contract development of high performance, high function, low-level software) -- 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

Just wondering which model PIC should I use. Thanks {Quote hidden}>From: Bob Ammerman <spamBeGoneRAMMERMAN@spam@PRODIGY.NET> >Reply-To: pic microcontroller discussion list <RemoveMEPICLISTspam_OUTMITVMA.MIT.EDU> >To: PICLISTspamMITVMA.MIT.EDU >Subject: Re: [pic] LED dot matix dsiplay >Date: Tue, 14 Nov 2000 02:58:01 -0500 > >BG Micro (http://www.bgmicro.com) has another option. Their ACS1076, which is a HP >HDSP-2303. > >This is also a 4-digit 5x7 dot matrix 0.2" LED display. This one, however, >is much smaller. The 14-pin package is the same size as a DIP16. The >characters are 0.2" on center, and they are end-to-end stackable. > >They are supposed to be quite bright (readable in direct sunlight!), but >they suck major current (as much as 500ma when fully lit) > >The price is quite a bit lower: $1.19 for 1-9, $.89 at 10+. > >These are no where near as smart as the others, however. > >Basically, they contain a 28 bit shift register to define the current input >for the 7 rows of each of the four digits. There are 5 separate column >inputs that must be driven in sequence. > >The basic operation: > >1: Load the 28 bit shift register with the pixels for column 1 of each >character. > >2: Enable the first column driver. > >3: Delay > >4: Disable the first column driver. > >repeat steps 1 through 4 for the other 4 columns. > >go back to step 1. > >The PIC, in this case must continuously refresh (multiplex) the display. > >A PWM drive can control the brightness. > >-- >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 > > _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

----- Original Message ----- From: Shahier Razik <spam_OUTsrazik00spam_OUTspam_OUTHOTMAIL.COM> To: <PICLISTspam_OUTMITVMA.MIT.EDU> Sent: Tuesday, November 14, 2000 11:58 PM Subject: Re: [pic] LED dot matix dsiplay > Just wondering which model PIC should I use. As always, this is a bit of a challenge. If you don't have any particularly stringent $$ constraints, and especially if this is a one-off and not a production item, I'd highly recommend the 16F87x (876 or 877 most probably). The ease of development on the flash chips, especially with an ICD in the case of the '87x, is a wonderful thing. In fact, many people develop on the '87x and then drop down to cheaper chips after the code is working. Just so you're careful to limit yourself to the features of your eventual target chip. Bob Ammerman RAm Systems (contract development of high performance, high function, low-level software) -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Any good links for lED display sample projects..... Thanks {Quote hidden}>From: Mike Mansheim <RemoveMEMichael_J_MansheimKILLspam@spam@GRACO.COM> >Reply-To: pic microcontroller discussion list <PICLISTspamBeGone.....MITVMA.MIT.EDU> >To: KILLspamPICLIST.....MITVMA.MIT.EDU >Subject: Re: [PIC]: LED dot matix dsiplay >Date: Wed, 15 Nov 2000 13:29:58 -0600 > > >> >In fact, many people develop on the '87x and then drop down to cheaper >chips >after the code is working. Just so you're careful to limit yourself to the >features of your eventual target chip. ><< >for example: F87x's have 10 bit a/d's, while C7x's (drop-in replacements) > have 8 bit a/d's > >-- >http://www.piclist.com hint: The PICList is archived three different >ways. See http://www.piclist.com/#archives for details. > > _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Thanks for the Link Tony However, the clock project is far too complicated for mine. All I'm doing is an LED diplay(messages) that will run off a battery. Using a pic. Generally, What parts will I need to complete this? Thanks {Quote hidden}>From: Tony Nixon <RemoveMETony.NixonRemoveMEEraseMEENG.MONASH.EDU.AU> >Reply-To: pic microcontroller discussion list <KILLspamPICLISTspamBeGoneMITVMA.MIT.EDU> >To: PICLISTspamMITVMA.MIT.EDU >Subject: Re: [PIC]: LED dot matix dsiplay >Date: Thu, 16 Nov 2000 13:20:48 +1100 > >Shahier Razik wrote: > > > > Any good links for lED display sample projects..... > >http://www.picnpoke.com/projects/clock.html > >-- >Best regards > >Tony > >mICro's >http://www.picnpoke.com >RemoveMEsalesspamBeGoneRemoveMEpicnpoke.com > >-- >http://www.piclist.com hint: The PICList is archived three different >ways. See http://www.piclist.com/#archives for details. > > _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.