usbpicprog-technical

[Usbpicprog-technical] new PCB and current software status

[Francesco M. <f18...@ya...>]

Hi Frans,
    I've noticed that you have committed a new version of the PCB (rev 0.3); it 
seems the new schematic will allow to support also lower-voltage PICs; I'll try 
to test it asap (if you say it's ready to be "beta-tested").

May I suggest a new feature? When building UPP for the first time I found out 
that most of the times the UPP failures were due to the pump not reaching 12V 
for some reason. I see that pin #12 (AN11) of the PIC18F2550 used in the 
programmer is not connected to anything.
Connecting it to VPP (through a voltage divider) would allow the firmware to 
self-test the charge-pump using its internal ADC.

I understand that this would further complicate the routing but if it turns out 
that this is not a big problem, then I think the two additional resistors are 
worth it :)

-----

Other question: does current software/firmware works for you?
I have revised almost all code of upp_wx, in particular the Hardware class, with 
the aim of reducing redundancy and add more safety checks... this helped me to 
better understand the internals of UPP but I still cannot currently 
program&verify any of the following devices I have tested:
- 16F84A
- 18F2550
- 18F4450
I don't know if the problem lies
a) in my UPP HW
b) in the cable a little bit too long I'm using to connect UPP with PICs under 
tests (unfortunately I cannot easily cut it)
c) in the read or program operations of the firmware

OTOH if I do a "program without verify" cycle UPP says everything was programmed 
fine (except for the 16F84A which says "verify error during programming"); I'll 
soon test if this is the case (putting the PIC in the real circuit where it 
needs to go).

I'm using firmware rev 547....

I don't think the problem is the software since in my cases it fails just 
because of the (error) codes returned by the firmware but just to be sure: does 
current software works for you?


Bye,
Francesco


-- 

Re: [Usbpicprog-technical] new PCB and current software status

[Frans S. <fra...@gm...>]

Hi Francesco,

I have just married, so in the last couple of weeks I had some other 
things to do :)
I have already changed the circuitry of the voltage pump, but I am 
afraid that a voltage divider would unnecessarily take current from the 
voltage pump. By the way, I have not released the 0.3 yet, because it 
needs some additional changes in the values of some resistors and some 
last checkups.

I will check the latest software tomorrow!

Cheers,

Frans

Francesco Montorsi wrote:
> Hi Frans,
>     I've noticed that you have committed a new version of the PCB (rev 0.3); it 
> seems the new schematic will allow to support also lower-voltage PICs; I'll try 
> to test it asap (if you say it's ready to be "beta-tested").
>
> May I suggest a new feature? When building UPP for the first time I found out 
> that most of the times the UPP failures were due to the pump not reaching 12V 
> for some reason. I see that pin #12 (AN11) of the PIC18F2550 used in the 
> programmer is not connected to anything.
> Connecting it to VPP (through a voltage divider) would allow the firmware to 
> self-test the charge-pump using its internal ADC.
>
> I understand that this would further complicate the routing but if it turns out 
> that this is not a big problem, then I think the two additional resistors are 
> worth it :)
>
> -----
>
> Other question: does current software/firmware works for you?
> I have revised almost all code of upp_wx, in particular the Hardware class, with 
> the aim of reducing redundancy and add more safety checks... this helped me to 
> better understand the internals of UPP but I still cannot currently 
> program&verify any of the following devices I have tested:
> - 16F84A
> - 18F2550
> - 18F4450
> I don't know if the problem lies
> a) in my UPP HW
> b) in the cable a little bit too long I'm using to connect UPP with PICs under 
> tests (unfortunately I cannot easily cut it)
> c) in the read or program operations of the firmware
>
> OTOH if I do a "program without verify" cycle UPP says everything was programmed 
> fine (except for the 16F84A which says "verify error during programming"); I'll 
> soon test if this is the case (putting the PIC in the real circuit where it 
> needs to go).
>
> I'm using firmware rev 547....
>
> I don't think the problem is the software since in my cases it fails just 
> because of the (error) codes returned by the firmware but just to be sure: does 
> current software works for you?
>
>
> Bye,
> Francesco
>
>
>   

Re: [Usbpicprog-technical] new PCB and current software status

[Ravi <chi...@vs...>]

Hi Frans

> I have already changed the circuitry of the voltage pump, but I am 
> afraid that a voltage divider would unnecessarily take current from the 
> voltage pump. By the way, I have not released the 0.3 yet, because it 
> needs some additional changes in the values of some resistors and some 
> last checkups.

If we have a 1 mA bleeder current, then 12K and 1.5K will provide 1.5V 
to the ADC.

VCC	13.5
R1	12
R2	1.5
V1	(VCC*R2)/(R1+R2) = 1.5V

If we have a 0.1 mA bleeder current, then 120K and 15K will provide 1.5V 
to the ADC.

VCC	13.5
R1	120
R2	15
V1	(VCC*R2)/(R1+R2) = 1.5V

Cheers

Ravi

Re: [Usbpicprog-technical] new PCB and current software status

[Francesco M. <f18...@ya...>]

Hi,

Frans Schreuder ha scritto:
> I have just married, so in the last couple of weeks I had some other 
> things to do :)
;) great, congratulations then!


> I have already changed the circuitry of the voltage pump, but I am 
> afraid that a voltage divider would unnecessarily take current from the 
> voltage pump.
that's true, indeed... maybe we could then have a "test pump mode" command in 
the firmware that makes the pump active so that one can test the UPP pump with 
its voltmeter without troubles of having to connect a PIC to it, issue a long 
programming command, etc etc.
The GUI would be a simple menu item under "Actions" named "Test charge pump" or 
something like that, whose effect would be to popup a modal dialog "Test the 
voltage on PIN 5 of the ICSP header; it should be 12V+/-xx%; click Cancel when 
done".

> By the way, I have not released the 0.3 yet, because it 
> needs some additional changes in the values of some resistors and some 
> last checkups.
ok! I'll wait then!

> I will check the latest software tomorrow!
Good!
Note that I've marked with FIXME a couple of points in the source code; in 
particular in hardware.cpp line 712 I suspect there could be a bug...

Bye,
Francesco


-- 

Re: [Usbpicprog-technical] new PCB and current software status

[Frans S. <fra...@gm...>]

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
  <meta content="text/html;charset=UTF-8" http-equiv="Content-Type">
  <title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
Hi Francesco,<br>
<blockquote cite="mid:4A0...@ya..." type="cite">
  <blockquote type="cite">
    <pre wrap="">I will check the latest software tomorrow!
    </pre>
  </blockquote>
  <pre wrap=""><!---->Good!
Note that I've marked with FIXME a couple of points in the source code; in 
particular in hardware.cpp line 712 I suspect there could be a bug...

  </pre>
</blockquote>
The latest software doesn't seem to program anything anymore in the pic
(tested 18F2550 and 16F870), I didn't change the firmware.<br>
I will have a look at the changes in the hardware you made...<br>
<br>
Cheers,<br>
<br>
Frans<br>
</body>
</html>