Post by thread:[PIC]: PicPocket

Hi all, Still going with the PicPocket programmer. 6K of code now. I was going to implement a small FAT system, but not sure if its worthwhile at this stage. The chips are flash, so upgrading should be a snap anyway. It now has user set verification voltages from 2V to 6V in 0.25V steps and can be easily calibrated at anytime by the user. I have an interface for the ICSP ready(?), but a few questions if anyone can help. The PIC's are supposed to be programmed with VccP at 5V, but can be verified afterwards at lower or higher voltages. How would this affect a target circuit that is designed to run on 2V? Is the ISCP supposed to power the target circuit? I've got ~200 mA available. Should these problems be addressed by the target circuit designer? TIA -- Best regards Tony mICro's http://www.picnpoke.com spam_OUTsalesTakeThisOuTpicnpoke.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Nice to hear about thr progress Tony First question I would say that if you are going to use 2volt in target you should go lower on verifcation. As to supplying power from the Programer to the target if you are only programing the chip you only feed the chip and not the rest of the circuit. you would only need to do this if you are planing to do ICD. Regards Art {Original Message removed}

Tony Nixon wrote: ....... >It now has user set verification voltages from 2V to 6V in 0.25V steps >and can be easily calibrated at anytime by the user. ......... >The PIC's are supposed to be programmed with VccP at 5V, but can be >verified afterwards at lower or higher voltages. > >How would this affect a target circuit that is designed to run on 2V? > >Is the ISCP supposed to power the target circuit? I've got ~200 mA >available. > Hi Tony, Some of these issues are touched in DS31028A - Section 28. In-Circuit Serial Programming™ (ICSP™). Says: - you may have to totally isolate the PIC from the rest of the ckt during programming - if the ckt can only run at low Vcc, eg 3v, due to use of 3v chips/etc. - most ICSP programmers have to be beefed up in order to guarantee risetimes on Vcc and Vpp over the range of possible application ckts. The doc shows a hi-current driver ckt for this. Sounds difficult to achieve total versatility, in being able to handle virtually "any" app board operating over full Vcc range. --------- I had another question regards your ckt. I assume [rightly??] that you have some kinda control PIC on your programmer bd. So, when you vary verification voltage over 2 - 6v, are you also varying Vcc to the control PIC? If no, then how are you interfacing to the pins of the target PIC, to deal with the large Vcc differences? 2v <-> 5v and 5v <-> 6v. If yes, then how did you choose a control PIC that can cover Vcc from 2-6v? Very few PICs will do this, except low-power devices running slow xtal freq. best regards, - dan michaels =============== -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Dan Michaels wrote: > Hi Tony, > > Some of these issues are touched in DS31028A - Section 28. In-Circuit > Serial Programming™ (ICSP™). Says: I'll download and check that out - thanks. > Sounds difficult to achieve total versatility, in being able to > handle virtually "any" app board operating over full Vcc range. CUMP can do it - kidding ;-) > I had another question regards your ckt. I assume [rightly??] > that you have some kinda control PIC on your programmer bd. So, > when you vary verification voltage over 2 - 6v, are you also > varying Vcc to the control PIC? No. > If no, then how are you interfacing to the pins of the target PIC, > to deal with the large Vcc differences? 2v <-> 5v and 5v <-> 6v. I am using open collector drivers for RB6/7 with pullups to the VccP rail. The data pin (RB7) has an input circuit as well, so it can be read. I tested the circuit over a 1 meter cable length and all seems ok. According to the ICSP sheet mentioned above, RB6/RB7 'may' need isolation depending on the target circuit connections. If that's the case then my circuit should work. As you mention, you can't hope to please everyone. -- Best regards Tony mICro's http://www.picnpoke.com .....salesKILLspam@spam@picnpoke.com -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! use listservKILLspammitvma.mit.edu?bodyT%20PICList%20DIGEST

Tony Nixon wrote: >> Sounds difficult to achieve total versatility, in being able to >> handle virtually "any" app board operating over full Vcc range. > >CUMP can do it - kidding ;-) > !!!!!!!!!!!!!!!!!!!!!!!! ======================== > >The data pin (RB7) has an input circuit as well, so it can be read. > >I tested the circuit over a 1 meter cable length and all seems ok. > You might check that whatever driver you are using to read back RB7 will work properly when the target Vcc is set down near 2v. Std logic like TTL or HC is not gonna work there. Adding a simple BJT inverter would probably be ok, I would imagine. ============== >According to the ICSP sheet mentioned above, RB6/RB7 'may' need >isolation depending on the target circuit connections. If that's the >case then my circuit should work. As you mention, you can't hope to >please everyone. > Obviously, the target board design people wanting to do ICSP have to be cognizant of the relevant issues, and design their boards accordingly. Publishing the reqs with your programmer will help guarantee compatibility. best regards, - danM ============== -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! use .....listservKILLspam.....mitvma.mit.edu?body=SET%20PICList%20DIGEST

Tony Nixon wrote: ........ >It now has user set verification voltages from 2V to 6V in 0.25V steps >and can be easily calibrated at anytime by the user. > ...... >The PIC's are supposed to be programmed with VccP at 5V, but can be >verified afterwards at lower or higher voltages. > Hi again Tony, Another potential hazard occurred to me. If the programmer does power the target during ICSP [which you apparently will have to do if you want to both program at 5v and then test over 2-6v], it is likely that the programmer will be back-driving current into the v.reg on the target bus. I dealt with this problem on the new PIC'40 SBC that I am producing by having a jumper for isolating the v.reg from the bus. You might want to suggest something similar in your PP ops manual. BTW, anyone got a good feel for how a v.reg reacts when you power it up from the wrong direction - or otherwise drive its ouput node higher than its input node? [proactive response --> hmmm, just as I thought]. regards, - Dan Michaels Oricom Technologies http://www.users.uswest.net/~oricom =================================== -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! use EraseMElistservspam_OUTTakeThisOuTmitvma.mit.edu?body=SET%20PICList%20DIGEST

>BTW, anyone got a good feel for how a v.reg reacts when you >power it up from the wrong direction - or otherwise drive its >ouput node higher than its input node? 7800 and 7900 series ones I had occasion to do this to put their legs in the air in disgust and died. -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestspam_OUTmitvma.mit.edu

Hi all, Just did a time test on the PicPocket. PIC16C74 Transfer 4K HEX code from PC to I2C EPROM- 14 seconds Now can be used any time Blank test Program and verify 4K of code + fuse Verify at lower Vcc Verify at upper Vcc 40 seconds Read 4K back and store to I2C EEPROM - 8 seconds. Verify at 5V only - 7 seconds Transfer 4K HEX code from I2C EEPROM to PC - 7 seconds. Not too bad considering the LCD display is being updated every 16 words to keep the user informed of the progress. Should be able to squeeze in 5 programs up to 8K each into the I2C memory. -- Best regards Tony mICro's http://www.picnpoke.com @spam@salesKILLspampicnpoke.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: "[PIC]:","[SX]:","[AVR]:" =uP ONLY! "[EE]:","[OT]:" =Other "[BUY]:","[AD]:" =Ads

Tony Nixon wrote: >Just did a time test on the PicPocket. ......... > >Not too bad considering the LCD display is being updated every 16 words >to keep the user informed of the progress. > Hi Tony, how large is the LCD and what are you displaying on it? -- http://www.piclist.com hint: PICList Posts must start with ONE topic: "[PIC]:","[SX]:","[AVR]:" =uP ONLY! "[EE]:","[OT]:" =Other "[BUY]:","[AD]:" =Ads

Andrew Kunz wrote: > > Tony, > > Does your programmer support control of RB3 for F87x? > > Andy > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > "[PIC]:","[SX]:","[AVR]:" =uP ONLY! "[EE]:","[OT]:" =Other "[BUY]:","[AD]:" =Ads Hi Andy, Yes, I have placed an open collector output available on the ISCP connector for whatever use. It is active low when VccP comes on. Might be useful for also pulling down the OSC1 pin. -- Best regards Tony mICro's http://www.picnpoke.com KILLspamsalesKILLspampicnpoke.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Dan Michaels wrote: > > Tony Nixon wrote: > > >Just did a time test on the PicPocket. > ......... > > > >Not too bad considering the LCD display is being updated every 16 words > >to keep the user informed of the progress. > > > > Hi Tony, how large is the LCD and what are you displaying on it? > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > "[PIC]:","[SX]:","[AVR]:" =uP ONLY! "[EE]:","[OT]:" =Other "[BUY]:","[AD]:" =Ads 2 X 16 There are many nested menus for the programmer functions as you might imagine. During programming etc, it basicly shows what ROM location the programmer is referencing. Plus it shows the dissassembled/modified code. -- Best regards Tony mICro's http://www.picnpoke.com RemoveMEsalesTakeThisOuTpicnpoke.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.