Post by thread:'Free' ICD

I looked at the circuit quite a bit last night and it is rather neat. The entire ICD is powered off the target circuit, and can be run from 3v to 5.5v. It uses a simple switching/voltage doubling arrangment to generate about 21 volts from a 5 volt supply, with the output of the PWM module (PORTC:2) driving the switching transister (Q5). This is then dropped to ~13 v with a 78L12. PORTC:1 and PORTC:5 control the voltage going to the VPP/MCLR pin of the target device. VPP is normally at VDD. PORTC:1, when high, switches the 13 volt supply onto VPP. PORTC:5, when high, grounds VPP. VPP is measured by DRA1 with a resister ladder such that DRA1 is one tenth (.1) of VPP. PORTC:0, 3, and 4 go to the target device at PORTB:3, 6, and 7, respectively. I won't detail the rest of the circuit here, it is straightforward from this point. You can find the circuit in the back (appendix A) for th MPLAD-ICD users guide. I was unable to procure a 3.6864MHz crystal, though. I'll try a colerburst crystal (3.58...) which is about 2.9% error... Hopefully it won't be too far off to be useful... -Adam

I wouldn't be substituting crystals - you'll mess up the timing on the serial routines. -Randy Glenn spam_OUTPICxpertTakeThisOuTtechie.com - http://i.am/PICxpert Ineptitude is a sure indicator of intellect. =========== To unsubscribe, send a message containing the text "unsubscribe PICLIST" to .....LISTSERVKILLspam@spam@MITVMA.MIT.EDU {Original Message removed}

>I was unable to procure a 3.6864MHz crystal, though. I'll try a colerburst >crystal (3.58...) which is about 2.9% error... Hopefully it won't be too far >off to be useful... standard baud rate generation crystal x2 = 7.3728 x3 = 11.0592 x4 = 14.7456 The 11.0592 is sometimes used for micro clocks, and could be divided by a pair of flip flops - get you out of copyright problems (you haven't copied the circuit exactly)

I'm just going to use a seperate power supply for the +13 VPP. It will eliminate nearly 1/3 of the circuitry... -Adam Alan Pearce wrote: {Quote hidden}> > >I was unable to procure a 3.6864MHz crystal, though. I'll try a colerburst > >crystal (3.58...) which is about 2.9% error... Hopefully it won't be too far > >off to be useful... > > standard baud rate generation crystal > > x2 = 7.3728 > x3 = 11.0592 > x4 = 14.7456 > > The 11.0592 is sometimes used for micro clocks, and could be divided by a pair > of flip flops - get you out of copyright problems (you haven't copied the > circuit exactly)

Can you post your modified schematics when you're done? Then again, there might be legal issues... As for the crystal: DIGI-KEY p/n 300-6002-ND. Very reasonable at $1.39 - CANADIAN. Probably less than a buck US. -Randy Glenn .....PICxpertKILLspam.....techie.com - http://i.am/PICxpert Ineptitude is a sure indicator of intellect. =========== To unsubscribe, send a message containing the text "unsubscribe PICLIST" to EraseMELISTSERVspam_OUTTakeThisOuTMITVMA.MIT.EDU {Original Message removed}

I've made a complete parts list, and have everything at home other than the crystal (I'm going to try a colorburst crystal first). (though the crystal X071-ND is only $0.64 [US]... A bit cheaper than your 1.39 canadian... ;-) Most likely what I will do is post the changes to the schematic in word form (ie, get the schematic from the users guide, ignore c11-c13, D1, L1, and hook +13 to the collector of Q3, etc, etc) But if I change the circuit significantly enough (for instance, I could cut out half the resisters, they are there for protection from shorts) then I might just post a simple full schematic... For those who are curious, a full kit for all parts needed to build the ICD(excepting the connectors and jacks, and including an 'f876 and an 'f877) is $40.93. It would only be $23.20 each kit if we bought 25 of them ($580.00 total for 25). I should have mine done tonight or tomorrow, as long as the wrong crystal works ok. -Adam Randy Glenn wrote: {Quote hidden}> > Can you post your modified schematics when you're done? Then again, there > might be legal issues... > > As for the crystal: DIGI-KEY p/n 300-6002-ND. Very reasonable at $1.39 - > CANADIAN. Probably less than a buck US. > > -Randy Glenn > PICxpertspam_OUTtechie.com - http://i.am/PICxpert > > Ineptitude is a sure indicator of intellect. >

I should mention here that the prices below are from DigiKey. I've got an excel spreadsheet, also in HTML, with a list of all the parts and their digikey part number and price. Email me if you'd like a copy. I probably won't put it on my website until I have one working. -Adam "M. Adam Davis" wrote: {Quote hidden}> > I've made a complete parts list, and have everything at home other than the > crystal (I'm going to try a colorburst crystal first). (though the crystal > X071-ND is only $0.64 [US]... A bit cheaper than your 1.39 canadian... ;-) > > Most likely what I will do is post the changes to the schematic in word form > (ie, get the schematic from the users guide, ignore c11-c13, D1, L1, and hook > +13 to the collector of Q3, etc, etc) > > But if I change the circuit significantly enough (for instance, I could cut out > half the resisters, they are there for protection from shorts) then I might just > post a simple full schematic... > > For those who are curious, a full kit for all parts needed to build the > ICD(excepting the connectors and jacks, and including an 'f876 and an 'f877) is > $40.93. It would only be $23.20 each kit if we bought 25 of them ($580.00 total > for 25). I should have mine done tonight or tomorrow, as long as the wrong > crystal works ok. > > -Adam > > Randy Glenn wrote: > > > > Can you post your modified schematics when you're done? Then again, there > > might be legal issues... > > > > As for the crystal: DIGI-KEY p/n 300-6002-ND. Very reasonable at $1.39 - > > CANADIAN. Probably less than a buck US. > > > > -Randy Glenn > > @spam@PICxpertKILLspamtechie.com - http://i.am/PICxpert > > > > Ineptitude is a sure indicator of intellect. > >

try http://www.esr.co.uk good people to deal with fast and easy all the best arthur spamBeGoneartbspamBeGonecableinet.co.uk ----- Original Message ----- From: Les <TakeThisOuTlesEraseMEspam_OUTTOP204.FREESERVE.CO.UK> To: <RemoveMEPICLISTTakeThisOuTMITVMA.MIT.EDU> Sent: Friday, March 17, 2000 8:45 PM Subject: Re: 'Free' ICD | Anyone know where I can buy the crystal here in the UK ?. | | Thanks | Les |

Hi Adam, A dumb question probably, but can you tell me where I can find ETN21 ? "The revised version describes the resistor changes necessary to replace the PIC16C73B on the MPLAB.........." I'm dammed if I can find it . Would you have a copy by any chance ? I'm guess that it is only available from the local dealer as part of an upgrade kit .... ??? .................... Zim

"M. Adam Davis" <EraseMEadavisUBASICS.COM> wrote: > A few people have contacted me about the pc board for the 'free' ICD. I am > currently using the majority of the circuit which the MPLAB-ICD is made of, > which is copyrighted by Advanced Transdata. They sell the MPLAB-ICD (about $149 > [us]) and another version which is more full-featured (about 10 dollars more). > > Due to the circumstances I doubt I will be making a PCB board anytime soon. As > things develop, I'll let everyone know. If I make a pcb, I'll plan a run of > 10-20. Email me if you want me to contact you at that time. > > -Adam Sorry if I missed a bit on this thread but is there anything going on about your 'Free' ICD (apart from http://www.piclist.com/freeicd )? I have checked your web site but can't find anything. Can you send me (or post to the PIClist) information about what exactly you have changed in original circuit? I'm *VERY* interested in building one since I have this project I must finish soon but I have problems debugging it. Thank you in advance. Miroslav Hibler RemoveMEmhiblerEraseMEEraseMEusa.net ____________________________________________________________________ Get free email and a permanent address at http://www.netaddress.com/?N=1