USB Pic programmers

[williB]

I get the idea that this error is caused by too low of voltage when programming. Is this correct and if so, how can I modify the schematic above to boost my power during programming?

from what i have read , yes the problem is the laptop's serial port, not being of high enough voltage.., but you have the usb to serial chip , so who knows?
it should work.

 

[evandude]

the reason is that the JDM-style programmers rely on the higher voltage levels of an actual RS232 serial port (+/- 10v or 12v) to generate the 13v for programming.

the problem is, most modern serial devices are perfectly happy with +/-5v or so, so that's all the USB-serial converters generally output.

it's the same reason that laptop built-in serial ports don't generally work with JDM programmers either... on newer laptops, they almost always use the reduced voltage levels as well.

I'm sure you could modify the circuit to use an external voltage source to generate the programming voltage... but it would make the programmer far less elegant and convenient... I never got around to trying, because I went and bought a USB programmer (kit 150 at kitsrus.com... they have a bunch of resellers)

 

[Mike - K8LH]

Evandude,

Just wanted to correct you on that K182 USB programmer pictured above... It's not a low voltage programmer... It's a high voltage programmer, developing 12-13 volts using a couple of those capacitors in a charge pump...

WilliB,

I've got a K182... It cost me something like $36 and change, including shipping, from that chap in Ohio... It's not worth copying for that money...

Beefer3,

Why bother trying to get a JDM design running on USB when you can buy something like the K182 for $36 and change?

Regards, Mike

 

[williB]

evan you mean to tell us that they made a usb to serial chip that didnt quite meet RS232 specs.. amazing ...
beefer3 what is the number of the chip offhand..?

 

[evandude]

mike... really? have you measured it?

that's weird, because they specify that it can only be used for FLASH chips... and I read somewhere that that was because of the low-voltage programming thing... but if it can provide full 12-13v programming voltage, why can it only do flash PICs? all the ones that aren't flash-specific have external power connections...

 

[Mike - K8LH]

Evendude,

I understood it was because the 'C' devices actually use some VPP current, where Flash devices are just lookin' for that high voltage level... But I'm not absolutely sure... I'm a relative newcomer of about one and a half years and I've never used anything but the Flash parts... Anyway, the charge pump schemes won't provide any significant current...

Regards, Mike

 

[evandude]

I guess that makes sense. if they are generating VPP using a capacitor charge-pump then it's going to have extremely limited current drive.

 

[Jay.slovak]

I've been reading this thread all along ..
and Correct me if i'm wrong , but no one seems to be using USB , mikes latest design , which is nice work btw , is serial ? no??
And Jays design is clearly serial , also very nice work ,
so my question is
why isnt anyone using the USB port??

this doesnt look to hard to copy.. granted it is just a USB programmer , with no ICD2 capabilities , but one of us should be able to at least figure out what is so mysterious about USB..

Currently ale ICD2 clones runs on Serial or Serial to USB cenvertor... Beacuse original ICD2 is using Cypress USB to Parallel convertor (Many believe it's an 8051 controller programmed by MPLAB). Full USB would be cool... but this is what you get if you made it yourself for 10% of the retial price of the original ICD2. 8)

 

[Nigel Goodwin]

Evendude,

I understood it was because the 'C' devices actually use some VPP current, where Flash devices are just lookin' for that high voltage level... But I'm not absolutely sure... I'm a relative newcomer of about one and a half years and I've never used anything but the Flash parts... Anyway, the charge pump schemes won't provide any significant current...

Yes, you are quite correct, some of the older chips require a reasonable amount of current feeding the Vpp pin - the more modern FLASH and EEPROM devices only require a voltage, with next to no current.

The actual requirements are specified in either the datasheet, or the programming sheet.

 

[Andy_123]

Here is ICD2 clone - USB to serial FT232BM based version.
Very small.
Single sided board, no external PS required,
EEPROM chip added.
All parts you see here, except FT and EEPROM (mounted at the bottom).

 

[Mike - K8LH]

Hi Andy,

I saw this picture on Lothar's site in the Forum... A very nice looking implementation...

I'm curious about the DC-to-DC convertor and other components you used... Do you have a schematic and BOM posted somewhere?

Regards, Mike

 

[Jay.slovak]

Here is ICD2 clone - USB to serial FT232BM based version.
Very small.
Single sided board, no external PS required,
EEPROM chip added.
All parts you see here, except FT and EEPROM (mounted at the bottom).

Nice PCB... I hope it will serve you well

 

[Jay.slovak]

Hi Andy,

I saw this picture on Lothar's site in the Forum... A very nice looking implementation...

I'm curious about the DC-to-DC convertor and other components you used... Do you have a schematic and BOM posted somewhere?

Regards, Mike

Mike, I solved MPLAB's serial problem! I don't have to enter setup everytime I start MPLAB or switch to debugger.

 

[Mike - K8LH]

Mike, I solved MPLAB's serial problem! I don't have to enter setup everytime I start MPLAB or switch to debugger.

Jay, how did you get the ICD2 com port setting to "stick"?

 

[Jay.slovak]

Mike, I solved MPLAB's serial problem! I don't have to enter setup everytime I start MPLAB or switch to debugger.

Jay, how did you get the ICD2 com port setting to "stick"?

It took me whole day... I made my own Config file, it Finally works! I have to redifine COM1 and COM2 Defaults to COM3 & COM4, but the main thing is, that now it works as should!

 

[Andy_123]

I will post PCB and schematics in a few days - I made small changes to accomodate different DC-DC converters on the same board.

The DC-DC converter shown is very expensive - $9 each - it is Burr-Brown 1W, but I have bunch of them here I got relatively cheap.
New board can handle in addition C&D converters as well as any 4 pin converters with 0.1" pin spacing.

 

[Jay.slovak]

I will post PCB and schematics in a few days - I made small changes to accomodate different DC-DC converters on the same board.

The DC-DC converter shown is very expensive - $9 each - it is Burr-Brown 1W, but I have bunch of them here I got relatively cheap.
New board can handle in addition C&D converters as well as any 4 pin converters with 0.1" pin spacing.

Cool, my ICD was constructed to be cheap, yours to be expensive lol.

 

[Andy_123]

Expensive? Not really.
For your clone add cost of external power supply with wall transformer, 5V and 13V regulators and it will be not that cheap.
USB version has no external wires at all, 5V taken from USB.

 

[Jay.slovak]

Expensive? Not really.
For your clone add cost of external power supply with wall transformer, 5V and 13V regulators and it will be not that cheap.
USB version has no external wires at all, 5V taken from USB.

Hmm, I share my adapter with speakers, And I had everything at home (except 16F876, that was $8.3), and I guess your USB->serial convertor and charge-pump were expensive (and certainly hard to get from where I am)...

 

[williB]

That FT232BM is a nice chip..
https://www.ftdichip.com/FTProducts.htm#FT232BM