Post by thread:[PIC]: Experiences making MPLAB-compatible ICD (In

Hi, folks!!! Well, days ago I have total success making a "do-it-yourself" ICD. I have followed the schematics from Patrick Touzet, and it works OK! Some things that I have encountered: 1) Communications: The ICD is formed like a DCE equipment, and needs a RS232 cable for computer-to-modem (NOT null-modem). I need some try-and-error before making a correct cable (this ended vey simple, a DB9 female to DB9 male straight cable). I change the capacitors attached to the MAX232 to 10 microfarads, and works OK (100 nanofarads is too small for some kinds of MAX232). With no computer attached,the LED blinks at 1Hz. The LED is fixed "on" when proper communications are established. 2)Voltages: I have canged the supply 100 microfarads capacitor for a 1000 microfarads (the power has drops with 100 micros). The LED must be a green LED. It needs to have a votage drop of 2V, because is used as voltage reference. One time the communication with ICD was established, one needs to adjust a little R1 and R21 for the correct reading of the VDD and VPP voltages. VDD can be measured with a multimeter, then adjust R1. VPP can be measured using an oscilloscope; when one touch the button "Self Test" in MPLAB, the ICD generates high voltage. The point of measure is the union of R21 with R17 and R18 (between 12 to 14 volts). Anoter method can be adjust R21 same proportion than R1 (for proper reading of VPP). 3) Crystal: The crystal of 3,6864 MHz is very hard to find. Yes, I know, it allows exact baud rate generation, but: why Microchip do not have used a much more common 3,58MHz (or 4MHz) crystal? Finnally, I have build a separate oscilator using a 7,3728MHz surplus crystal and a 74HC04 plus 74LS74 as a divider. (ugh!! ugly but works! I was lucking obtaining this rare crystal from an old RS232 PC add-on card). The Touzet's site is: http://www.multimania.com/silicium31/ more exactly: http://www.multimania.com/silicium31/Electronique/PIC/free_icd.htm I am interested in read experiences of other peoples that have build ICDs. Cheers!!! Alejandro spam_OUTalejolTakeThisOuTadinet.com.uy -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body

Alejandro Lavarello wrote: > Hi, folks!!! > > Well, days ago I have total success making a "do-it-yourself" ICD. > I have followed the schematics from Patrick Touzet, and it works OK! I built mine using the schematics in the user guide, (which is on the Microchip CD rom along with the firmware required) on a piece of veroboard. After a bit of fiddling it worked well. > Some things that I have encountered: > > 1) Communications: The ICD is formed like a DCE equipment, and needs a > RS232 cable for computer-to-modem (NOT null-modem). I need some try-and-error > before making a correct cable (this ended vey simple, a DB9 female to DB9 > male straight cable). > I change the capacitors attached to the MAX232 to 10 microfarads, > and works OK (100 nanofarads is too small for some kinds of MAX232). I also changed the caps to 10uf tant. beads > > With no computer attached,the LED blinks > at 1Hz. The LED is fixed "on" when proper communications are established. > > 2)Voltages: I have canged the supply 100 microfarads capacitor for a 1000 > microfarads > (the power has drops with 100 micros). I didn't have this problem which cap. are you referring to ? > > The LED must be a green LED. It needs to have a votage drop of 2V, My led is red ! However I had to try several from the junk box to find one which worked. {Quote hidden}> because > is used as voltage reference. One time the communication with ICD was > established, > one needs to adjust a little R1 and R21 for the correct reading > of the VDD and VPP voltages. > VDD can be measured with a multimeter, then adjust > R1. VPP can be measured using an oscilloscope; when one touch the button > "Self Test" in MPLAB, the ICD generates high voltage. The point of measure is > the union of R21 with R17 and R18 (between 12 to 14 volts). > Anoter method can be adjust R21 same proportion than R1 (for proper reading > of VPP). Initially I had problems getting a high enough Vpp. I found changing Q4 2N2222A for a proper switching transistor - ZTX650 ( had a few spare - they were used in ZX spectrums, switching a coil to produce -Vdd for memory IC's they failed often when people plugged in expansion packs without disconnecting the power!) gave me a higher voltage and no need to fiddle with resistors. > > > 3) Crystal: The crystal of 3,6864 MHz is very hard to find. I *think* I bought mine from RS components. {Quote hidden}> Yes, I know, it > allows exact > baud rate generation, but: why Microchip do not have used > a much more common 3,58MHz (or 4MHz) crystal? Finnally, I have build a > separate > oscilator using a 7,3728MHz surplus crystal and a 74HC04 plus 74LS74 as a > divider. > (ugh!! ugly but works! I was lucking obtaining this rare crystal from an > old RS232 > PC add-on card). My ICD has been working reliably for several months now. I now wonder how I managed without it. I just received a mailshot from A microchip distributor here in the UK. They are offering the ICD for 66 UK pounds, including an F873 while stocks last. So its now hardly worth building one. {Quote hidden}> > > The Touzet's site is: > > http://www.multimania.com/silicium31/ > > more exactly: > > http://www.multimania.com/silicium31/Electronique/PIC/free_icd.htm > > I am interested in read experiences of other peoples that have build > ICDs. > > Cheers!!! > Alejandro alejolKILLspamadinet.com.uy > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email .....listservKILLspam.....mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Hi Steven! Well, the advantage of the Touzet's PCB is that is small-sized single side. But some traces are much closer togheter (difficult to draw it by hand). With a red led, the voltage readings was very high (1.3 V drop in my first red LED). The fiddle with resistors may be unnecessary with the correct LED, 2N222A and proper inductor, I think... Was a bit difficult for me to obtain the 2N2222A, (another travel to my obsolete PC-hardware cards box :) The inductor I have used is great in size, maybe a TV-part or a valvular-radio choke. The Touzet´s ICD has a built-in 78L05 regulator and can supply voltage to the target or be feeded for it (jumper selectable). (The Microchip´s ICD is feed by the voltage of the target). Because it, a capacitor of 100uF is used in Touzet´s circuit for filtering the incoming rectified voltage. With a trasformer of 9 VCA, is best to change this capacitor to 1000 uF in order to obtain clean VDD. If I was money, I buy the original ICD, but here it costs more than U$S 350 (because taxes and exaggerated resellers earnings). Cheers! Alejandro. At 12:34 29/05/01 +0100, you wrote: >Alejandro Lavarello wrote: > >> Hi, folks!!! >> >> Well, days ago I have total success making a "do-it-yourself" ICD. >> I have followed the schematics from Patrick Touzet, and it works OK! > >I built mine using the schematics in the user guide, (which is on the Microchip >CD rom along with the firmware required) on a piece of veroboard. After a bit of >fiddling it worked well. > >> Some things that I have encountered: >> >> 1) Communications: The ICD is formed like a DCE equipment, and needs a >> RS232 cable for computer-to-modem (NOT null-modem). I need some try-and-error {Quote hidden}>> before making a correct cable (this ended vey simple, a DB9 female to DB9 >> male straight cable). >> I change the capacitors attached to the MAX232 to 10 microfarads, >> and works OK (100 nanofarads is too small for some kinds of MAX232). > >I also changed the caps to 10uf tant. beads > >> >> With no computer attached,the LED blinks >> at 1Hz. The LED is fixed "on" when proper communications are established. >> >> 2)Voltages: I have canged the supply 100 microfarads capacitor for a 1000 >> microfarads >> (the power has drops with 100 micros). > >I didn't have this problem which cap. are you referring to ? > >> >> The LED must be a green LED. It needs to have a votage drop of 2V, > >My led is red ! However I had to try several from the junk box to find one which >worked. > >> because >> is used as voltage reference. One time the communication with ICD was >> established, >> one needs to adjust a little R1 and R21 for the correct reading >> of the VDD and VPP voltages. >> VDD can be measured with a multimeter, then adjust >> R1. VPP can be measured using an oscilloscope; when one touch the button >> "Self Test" in MPLAB, the ICD generates high voltage. The point of measure is >> the union of R21 with R17 and R18 (between 12 to 14 volts). >> Anoter method can be adjust R21 same proportion than R1 (for proper reading >> of VPP). > >Initially I had problems getting a high enough Vpp. I found changing Q4 2N2222A >for a proper switching transistor - ZTX650 ( had a few spare - they were used in >ZX spectrums, switching a coil to produce -Vdd for memory IC's they failed often >when people plugged in expansion packs without disconnecting the power!) gave me {Quote hidden}>a higher voltage and no need to fiddle with resistors. > >> >> >> 3) Crystal: The crystal of 3,6864 MHz is very hard to find. > >I *think* I bought mine from RS components. > >> Yes, I know, it >> allows exact >> baud rate generation, but: why Microchip do not have used >> a much more common 3,58MHz (or 4MHz) crystal? Finnally, I have build a >> separate >> oscilator using a 7,3728MHz surplus crystal and a 74HC04 plus 74LS74 as a >> divider. >> (ugh!! ugly but works! I was lucking obtaining this rare crystal from an >> old RS232 >> PC add-on card). > >My ICD has been working reliably for several months now. I now wonder how I >managed without it. > >I just received a mailshot from A microchip distributor here in the UK. They are {Quote hidden}>offering the ICD for 66 UK pounds, including an F873 while stocks last. > >So its now hardly worth building one. > >> >> >> The Touzet's site is: >> >> http://www.multimania.com/silicium31/ >> >> more exactly: >> >> www.multimania.com/silicium31/Electronique/PIC/free_icd.htm >> >> I am interested in read experiences of other peoples that have build >> ICDs. >> >> Cheers!!! >> Alejandro alejolspam_OUTadinet.com.uy >> >> -- >> http://www.piclist.com#nomail Going offline? Don't AutoReply us! >> email @spam@listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body > >-- >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.

It would be wonderful if this experience made its way onto the piclist.com freeicd paqe. Hint, hint. James Newton (PICList Admin #3) RemoveMEjamesnewtonTakeThisOuTpiclist.com 1-619-652-0593 Steven Allard wrote on 01-5-29 4:47: Alejandro Lavarello wrote: > Hi, folks!!! > > Well, days ago I have total success making a "do-it-yourself" ICD. I have followed the schematics from Patrick Touzet, and it works OK! I built mine using the schematics in the user guide, (which is on the Microchip CD rom along with the firmware required) on a piece of veroboard. After a bit of fiddling it worked well. > Some things that I have encountered: > > 1) Communications: The ICD is formed like a DCE equipment, and needs a RS232 cable for computer-to-modem (NOT null-modem). I need some try-and-error before making a correct cable (this ended vey simple, a DB9 female to DB9 male straight cable). > I change the capacitors attached to the MAX232 to 10 microfarads, and works OK (100 nanofarads is too small for some kinds of MAX232). I also changed the caps to 10uf tant. beads > > With no computer attached,the LED blinks at 1Hz. The LED is fixed "on" when proper communications are established. > > 2)Voltages: I have canged the supply 100 microfarads capacitor for a 1000 microfarads > (the power has drops with 100 micros). I didn't have this problem which cap. are you referring to ? > > The LED must be a green LED. It needs to have a votage drop of 2V, My led is red ! However I had to try several from the junk box to find one which worked. > because > is used as voltage reference. One time the communication with ICD was established, > one needs to adjust a little R1 and R21 for the correct reading of the VDD and VPP voltages. > VDD can be measured with a multimeter, then adjust R1. VPP can be measured using an oscilloscope; when one touch the button > "Self Test" in MPLAB, the ICD generates high voltage. The point of measure is the union of R21 with R17 and R18 (between 12 to 14 volts). Anoter method can be adjust R21 same proportion than R1 (for proper reading of VPP). Initially I had problems getting a high enough Vpp. I found changing Q4 2N2222A for a prop ************************* This message has been truncated. The entire message is available on your desktop e-mail client. -- 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

It would be wonderful if this experience made its way onto the piclist.com freeicd page. Hint, hint. James Newton (PICList Admin #3) spamBeGonejamesnewtonspamBeGonepiclist.com 1-619-652-0593 Steven Allard wrote on 01-5-29 4:47: Alejandro Lavarello wrote: > Hi, folks!!! > > Well, days ago I have total success making a "do-it-yourself" ICD. I have followed the schematics from Patrick Touzet, and it works OK! I built mine using the schematics in the user guide, (which is on the Microchip CD rom along with the firmware required) on a piece of veroboard. After a bit of fiddling it worked well. > Some things that I have encountered: > > 1) Communications: The ICD is formed like a DCE equipment, and needs a RS232 cable for computer-to-modem (NOT null-modem). I need some try-and-error before making a correct cable (this ended vey simple, a DB9 female to DB9 male straight cable). > I change the capacitors attached to the MAX232 to 10 microfarads, and works OK (100 nanofarads is too small for some kinds of MAX232). I also changed the caps to 10uf tant. beads > > With no computer attached,the LED blinks at 1Hz. The LED is fixed "on" when proper communications are established. > > 2)Voltages: I have canged the supply 100 microfarads capacitor for a 1000 microfarads > (the power has drops with 100 micros). I didn't have this problem which cap. are you referring to ? > > The LED must be a green LED. It needs to have a votage drop of 2V, My led is red ! However I had to try several from the junk box to find one which worked. > because > is used as voltage reference. One time the communication with ICD was established, > one needs to adjust a little R1 and R21 for the correct reading of the VDD and VPP voltages. > VDD can be measured with a multimeter, then adjust R1. VPP can be measured using an oscilloscope; when one touch the button > "Self Test" in MPLAB, the ICD generates high voltage. The point of measure is the union of R21 with R17 and R18 (between 12 to 14 volts). Anoter method can be adjust R21 same proportion than R1 (for proper reading of VPP). Initially I had problems getting a high enough Vpp. I found changing Q4 2N2222A for a prop ************************* This message has been truncated. The entire message is available on your desktop e-mail client. -- 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