Hi Xiao Fan,

Quite interesting alternatives. My testing board was built on a matrix
board. Should not be a problem to add those suggestions to my
experiments later. Not my top priority at the moment. I am excited by 
the progress so far. With a PIC12F675, it seems like performing well. 
I have written data to program memory + EEROM data
and all read back correctly. My priority now is to keep playing with 
the board and see if I could add some enhancement to the command sets. 
For instance the command to change the Vpp...and perhaps looking into 
the chance to improve the PID. Not really must get a result from the 
latter. Just want to study a bit more about the PID.

By the way, in the MPLAB project that I sent to you, I used 'retfie 
fast'. I was doing this to 'experience' how bad the silicon bug is 
with C18. You should not use return fast and put back the context 
saving code that I have commented out.


Best regards,
WH Tan

PS: Are we share the same last name actually?




----- Original Message ----- 
From: "Chen Xiao Fan" <xiaofan@sg.pepperl-fuchs.com>
To: "'Microcontroller discussion list - Public.'" <piclist@mit.edu>
Sent: Friday, July 08, 2005 9:52 AM
Subject: RE: [PIC] PICKIT 2 (was PICKit1 & PIC18F2550)


> Another option for improvement of the PICkit 1 Vpp power generation
> is to use a separate small SMPS like the one inside ICD2. I have
> since measured the Vpp waveform of the ICD2 Vpp line and it is quite
> nice (not like PICkit 1).
>
> Based on a well circulated ICD2 clone circuit, the ICD2 Vpp
> generation
> is a boost (step-up) converter based on an OnSemi MC34063 (quite
> cheap),
> a 100uH inductor, a BAT85 (?) Schottky diode, a 47uF capacitor.
> To smooth the output voltage, it has employed another 10uH inductor
> and a 47uF capacitor. The feedback is a voltage divider consisting
> two
> resistor and a digital poti. The digital poti can be simply replaced
> by a analog poti if no automatic adjustment of Vpp is required.
> I have opened the original ICD2 and find it to be similarly built
> (or I should say the clone is following the original ICD2 design).
>
> Another option is to use a 10F20x, just like the one used in Olin's
> prototype board discussed sometime ago.
>
> Let us wait and see the design of PICkit 2.
>
> Regards,
> Xiaofan



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