Exo said:Don't know about picall, but some programmers, like jdm, have problems with the 12f675 when running on internal oscillator. They turn VDD on before VPP and the pic starts running its program wich prevents it from going into programming mode, maybe the picall's problem is similar...
What a coincidence! I have been playing with my ICD2 and 16F675 all day today.... I had some strange 0x00 problem too. Then, after I re-read the Datasheet, I realised Swapped VSS and VDD in my design (strange, it's different at 16F628). After that it works like charm... Also check if you are not Overloading PGD $ PGC pins of the ICD2 (eg LEDs...).Alex_rcpilot said:Hi guys.problems back,with the ICD2.But I think this time it's pretty much the problem about my understanding about the 12F675 rather than a programmer malfunction.
I was thinking about migrating a servo control system I built previously with ATtiny15L into a PIC12F675,found it impossible to access the PIC however(chip ID read 0x00),I noticed the 12F675 is somehow a little different according to some limited info I have in hand but not sure how exactly.Here's my hardware configuration:
It's a minimized circuit:Vdd = +5V,GND = ground,Vpp,CLK,DAT all connected to corresponding pins on the ICD2's cable.The chip has never been touched since shipment not long ago.
Do I have to do something to the hardware to help the ICD2 access ICSP mode?I searched this forum and found this:
Exo said:Don't know about picall, but some programmers, like jdm, have problems with the 12f675 when running on internal oscillator. They turn VDD on before VPP and the pic starts running its program wich prevents it from going into programming mode, maybe the picall's problem is similar...
Is there a same problem with ICD2?What if I add a transistor to Vdd that switches on it right after Vpp is applied?My gratitude in advance!
The one that is stuck into breadboard is standart 5pin Female+Male connector (SIP, like 3pin FAN connector), the other end is soldered inside the box/case..williB said:jay is that a cable with a sip connector on thr end..?
williB said:Alex i believe the F675 does not have on chip debugging..
i think that may be the problem
Nigel Goodwin said:I can't help you with the IDC2, but I can clear up the confusion about internal oscillators!.
As you probably know?, to place a PIC in programming mode you need to place about 13V on the MCLR pin. But as well as this, the PIC must not be running at the time, or it's impossible to enter programming mode!.
The programming sequence consists of turning ON Vdd, then turning ON Vpp (that feeds the MCLR pin), if you have a PIC that contains an internal oscillator Vpp must follow Vdd BEFORE the oscillator can start! - and it's normal to have a delay between the two switching events. In order to make it work with internal oscillators this delay must be shorter than the oscillator startup time of the PIC - which is specified in the datasheet.
So there's no problem, as long as the delay time is short enough - I modified WinPicProg to make it a user setting - so you can shorten it as you wish. I originally hit the problem with the 16F628, but it applies to any PIC with an nternal oscillator.
So, to sum everything up:Alex_rcpilot said:williB said:Alex i believe the F675 does not have on chip debugging..
i think that may be the problem
Well,ah...actually I'm a little confused with it.MUST a chip have on chip debugging function to be programmed serially?I found 12F675 in the MPLAB readme file for ICD2.So it's pretty certain that ICD2 supports this chip.And I only need to program it other than debugging.
Nigel Goodwin said:I can't help you with the IDC2, but I can clear up the confusion about internal oscillators!.
As you probably know?, to place a PIC in programming mode you need to place about 13V on the MCLR pin. But as well as this, the PIC must not be running at the time, or it's impossible to enter programming mode!.
The programming sequence consists of turning ON Vdd, then turning ON Vpp (that feeds the MCLR pin), if you have a PIC that contains an internal oscillator Vpp must follow Vdd BEFORE the oscillator can start! - and it's normal to have a delay between the two switching events. In order to make it work with internal oscillators this delay must be shorter than the oscillator startup time of the PIC - which is specified in the datasheet.
So there's no problem, as long as the delay time is short enough - I modified WinPicProg to make it a user setting - so you can shorten it as you wish. I originally hit the problem with the 16F628, but it applies to any PIC with an nternal oscillator.
Yes Nigel,I understand about the sequence.But I don't think this DIYed ICD2 can set the Vdd-Vpp power up interval.Because the target board power supply mode selection is ignored by a hardware jumper.I can set the jumper to output Vdd or disable it.MPLAB never has access to the power management.This causes a problem:The Vpp can never be applied soon enough before the internal oscillator starts to function without my extra attempt in building a special circuitry.May I ask if the Vpp can be powered up prior to Vdd,with both CLK and DAT pulled down?And,as you know,12F675 is not the only chip with internal oscillators.Many other chips have them,e.g,16F877(A).Why does 675 have such configuration problem while 877 doesn't?I browsed throught the documents but couldn't find issues on default config values.If they're all "1"s,then external RC oscillators are designated for both 877 and 675.Signifying the 675 won't be powered up with internal oscillator running by default.I'm so confused!
This is from MPLAB help file.Pay attention to the sentence saying the chip must be clock.That makes me even more messed up!
PIC12F629/675, PIC16F630/676, PIC16F627A/628A/648A Limitations
Debugger Limitations
Programmer Limitations
Programming these devices while debugging may be slower as these devices do not have row erase capability.
Only ICD Versions
Only ICD devices (e.g., PIC12F629-ICD) can be used to debug with MPLAB ICD 2.
Only ICD devices can be programmed using the MPLAB ICD 2 Header. Use the Universal Programming Module (AC162049) to program non-ICD devices.
ICD devices must be clocked (internally on INTOSC or externally on OSC1) and have MCLR high to communicate with the MPLAB ICD 2.
A breakpoint cannot be set on a GPIO instruction. Since MPLAB ICD 2 I/O is through bits 6 and 7 of GPIO, setting a breakpoint on a GPIO instruction will cause communication problems.
Devices cannot be programmed or read while GP1/RA1 is high (Vih). Move circuitry that makes GP1/RA1 high to another I/O pin during development.
Alex_rcpilot said:Many other chips have them,e.g,16F877(A).Why does 675 have such configuration problem while 877 doesn't?I browsed throught the documents but couldn't find issues on default config values.If they're all "1"s,then external RC oscillators are designated for both 877 and 675.Signifying the 675 won't be powered up with internal oscillator running by default.I'm so confused!
ICDWarn0033: MPLAB ICD 2 does not support programming this device if both the internal oscillator and internal MCLR are selected. You may continue programming, but you are encouraged to cancel, reconfigure your device, and try again.
Thanks, I love simplicityMike said:<off topic>
Jay (not Alex, grin),
I love the way you packaged your ICD2 Clone... Bravo Sir...
Regards, Mike
Anything particular?williB said:Could somone put up a screen shot of what is on the screen when doing ICD2 ?
Thanks again....Mike said:Jay,
Very nice Sir... Very clean lines... Bravo again...
Feel free to upload it, I am not in the mood of taking ScreenShots...Mike said:I'll try to upload a sample image later, if Jay hasn't beaten me to it...
Regards, Mike
Mike, K8LH wrote:
I'll try to upload a sample image later, if Jay hasn't beaten me to it...
Feel free to upload it, I am not in the mood of taking ScreenShots... Very Happy
Ok, I will do it 8)Mike said:Mike, K8LH wrote:
I'll try to upload a sample image later, if Jay hasn't beaten me to it...
Feel free to upload it, I am not in the mood of taking ScreenShots... Very Happy
Same here Jay... I'm right in the middle of something... I can sneak in a minute now and then to add a post to the Forum but I don't have time to bring up MPLAB and do a screen shot right now...
Regards, Mike
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