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Jason Hsu | 9 Feb 23:06
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[PIC]A/D conversion clock rate

For the PIC16F872 and PIC16F72 microcontrollers, there are 4 different
clock rates available for A/D conversion.

Other than copying the rate somebody else used for a similar project,
how do you pick the appropriate clock rate?  Is this a trade-off
between speed and accuracy?  If so, how much accuracy must you
sacrifice for a higher clock rate?  If not, what other factors come
into play?

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ivp | 10 Feb 00:47
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Re: [PIC]A/D conversion clock rate

*



> how do you pick the appropriate clock rate?


Jason, there are two timng periods. TAQ is the acquisition time, the
time needed to charge the ADC capacitor. TAD is the unit of time
needed for the conversion of the analogue voltage to a digital value

There's a formula to calculate TAQ vs source impedance to ensure
that sufficient time is allowed for charging. For example if you have
a source at the low end of source impedance (say something like a
1k or 500R pot) then you meet the minimum time to charge the input
capacitor. If source impedance is greater then you might have to use
a custom time delay. If the pot was as high as 100k perhaps then
you'd have to calculate how much long for the acquisition. At one time
PICs had only user-defined delays. Now TAQ has settable delay bits
in a register

A TAD is 1.6us, the time for a 1-bit conversion. For a 10-bit ADC the
complete conversion takes 11 TAD. Therefore you use the table or
calculation in the datasheet to determine the ADCS <1:0> setting so
that a TAD > = 1.6us

I believe that TAD < 1.6us results in an incomplete conversion and
that TAD (grossly, for example) > 1.6us is unnecessarily slow

Some background reading. Microchip have plenty of ADC reference
documents too

http://en.wikipedia.org/wiki/Analog-to-digital_converter

http://www.mikroe.com/en/books/picmcubook/ch7/
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Mark E. Skeels | 9 Feb 15:04

[PIC] PICKIT 3 command line programming

Has anyone had a successful experience with the PICKIT 3 command line 
utility pk3cmd.exe?

???

Mark Skeels
Engineer
Competition Electronics, Inc.
TEL: 815-874-8001
FAX: 815-874-8181
www.competitionelectronics.com

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Scott | 9 Feb 15:22
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Re: [PIC] PICKIT 3 command line programming

On Tue, Feb 9, 2010 at 9:04 AM, Mark E. Skeels
<mskeels <at> competitionelectronics.com> wrote:

*



> Has anyone had a successful experience with the PICKIT 3 command line
> utility pk3cmd.exe?
>
> ???
>


Yes. I've created a .bat script to program an 18F2510 at 5V.

It's one line:

PK3CMD -P18F2510 -FserialC.hex -V5.000 -M -Y

I forget what the M and Y switches are (perhaps I should comment the script).

You need the drivers for the PK3 installed on the machine.

-Scott
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Xiaofan Chen | 9 Feb 15:55
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Re: [PIC] PICKIT 3 command line programming

*



On Tue, Feb 9, 2010 at 10:22 PM, Scott <goldscott <at> gmail.com> wrote:
> You need the drivers for the PK3 installed on the machine.

Actually PICkit 3 is an HID device and you do not need drivers for it
(using Windows HID driver). But in order to use pk3cmd, basically
you need to install MPLAB.

The only one which does not need MPLAB is pk2cmd for
PICkit 2 and the one for Promate II and PM3.

For the console program of ICD 3, Real ICE and
PICkit 3, you basically need to install MPLAB.

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Mark E. Skeels | 9 Feb 16:44

Re: [PIC] PICKIT 3 command line programming

Would like to report that an upgrade to MPLAB rev. 8.43 installed 
firmware revision 01.25.14 into my Pickit 3 and all now works properly.

Thanks for the help and input......

Mark Skeels
Engineer
Competition Electronics, Inc.
TEL: 815-874-8001
FAX: 815-874-8181
www.competitionelectronics.com

Xiaofan Chen wrote:

*



> On Tue, Feb 9, 2010 at 10:22 PM, Scott <goldscott <at> gmail.com> wrote:
>   
>> You need the drivers for the PK3 installed on the machine.
>>     
> Actually PICkit 3 is an HID device and you do not need drivers for it
> (using Windows HID driver). But in order to use pk3cmd, basically
> you need to install MPLAB.
>
> The only one which does not need MPLAB is pk2cmd for
> PICkit 2 and the one for Promate II and PM3.
>
> For the console program of ICD 3, Real ICE and
> PICkit 3, you basically need to install MPLAB.
>
>   

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Scott Zielinski | 9 Feb 16:47

Re: [PIC] PICKIT 3 command line programming

*



On 2/9/2010 8:22 AM, Scott wrote:
> On Tue, Feb 9, 2010 at 9:04 AM, Mark E. Skeels
> <mskeels <at> competitionelectronics.com>  wrote:
>    
>> Has anyone had a successful experience with the PICKIT 3 command line
>> utility pk3cmd.exe?
>>
>> ???
>>
>>      
> Yes. I've created a .bat script to program an 18F2510 at 5V.
>
> It's one line:
>
> PK3CMD -P18F2510 -FserialC.hex -V5.000 -M -Y
>
> I forget what the M and Y switches are (perhaps I should comment the script).
>
> You need the drivers for the PK3 installed on the machine.
>
> -Scott
>    

Options              Description                              Default
----------------------------------------------------------------------------
M<memory region>     Program Device                           Do Not Program
                      memory regions:
                          P = Program memory
                          E = EEPROM
                          I = ID memory
                          C = Configuration memory
                          If no region is entered, the entire
                          device will be erased & programmed.
                          If a region is entered, no erase
                          is performed and only the given
                          region is programmed.
                          All programmed regions are verified.
              (serial EEPROM memory is 'P')
Y<memory region>     Verify Device                            Do Not Verify
                          P = Program memory
                          E = EEPROM
                          I = ID memory
                          C = Configuration memory
                          If no region is entered, the entire
                          device will be verified.
                          (Serial EEPROM memory is 'P')

Scott

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Xiaofan Chen | 9 Feb 15:21
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Re: [PIC] PICKIT 3 command line programming

On Tue, Feb 9, 2010 at 10:04 PM, Mark E. Skeels
<mskeels <at> competitionelectronics.com> wrote:

*



> Has anyone had a successful experience with the PICKIT 3 command line
> utility pk3cmd.exe?


I have big problems with PICkit 3 (connecting problems).
http://www.microchip.com/forums/tm.aspx?m=467684

But once it is connected, pk3cmd is working as expected.

C:\Program Files\Microchip\MPLAB IDE\Programmer Utilities\PICkit3>pk3cmd -P18F45
K20 -V3.3

Connecting...
PICkit 3 detected
Connecting to PICkit 3...
Running self test...
Self test passed
Firmware Suite Version...... 01.25.14
Firmware type......................PIC18F
PICkit 3 Connected.
Device ID Revision = 00000016

C:\Program Files\Microchip\MPLAB IDE\Programmer Utilities\PICkit3>pk3cmd -P18F45
K20 -V3.3 -GFtest.hex

Connecting...
PICkit 3 detected
Connecting to PICkit 3...
Firmware Suite Version...... 01.25.14
Firmware type......................PIC18F
PICkit 3 Connected.
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Electron | 9 Feb 10:01
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[EE]: High pulse current capacitors


Hi!
I need some capacitors with very high pulse current capability. Looking
at digikey catalog, I don't know how to select them (short of checking
every cap's datasheet), should I look at the ESR rating only? Will this
suffice? (I will then look at max current and stay within that average
value of course)

In general, what kind of cap is more suitable for high pulse current?

Thanks!
Mario & Osvaldo

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Josh Koffman | 9 Feb 06:36
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[PIC] 9 bit binary to digits?

Hi all. I'm thinking of a project where I'll have a 9 bit binary
number, and I'll want to display it on a 3 digit 7 segment display. To
do this I'll need to extract the hundreds, tens, and ones digits from
the number. The PICList.org website has an 8 bit version to do this
(http://www.piclist.org/techref/microchip/math/radix/b2oth-8b3d-jsv.htm).
Has anyone seen a 9 bit version (or a higher bit version that's easily
foolable, I guess up to 16 bit would be easy)?

Binary maths and translations aren't my strong point so I'd love to
see an example rather than trying to write one myself.

Thanks!

Josh
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ivp | 9 Feb 07:41
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Re: [PIC] 9 bit binary to digits?

*



> The PICList.org website has an 8 bit version to do this


How about subtract 100 from the number until the 9th bit is clear,
then use the 8-bit routine to get the rest. Add the number of subtracts
to the 100's digit. That would be a maximum of 4 subtracts, to find
256 - 300, 301 - 400, 401 - 500 and > 501

wbr
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Gmane