Re: [Usbpicprog-technical] USB electrical characteristics

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

Frans Schreuder ha scritto:
>     ok; but what about Vpp?
>     The charge pump can deliver only a very small current; I've
>     simulated it (using a square wave on Vpump1 and Vpump2 at about
>     20kHz) and absorbing 1.5mA makes Vpp drop to 9V....
> 
>     OTOH I couldn't find any specs about the minimal current which this
>     pin should be able to provide... I've found references to a LVP
>     (low-voltage programming) mode, where Vpp is used only as a voltage
>     reference (if I got it right); while in non-LVP mode, Vpp is used as
>     source for the EEPROM programming.
>     I may be wrong however...
> 
> 
> According to Microchip's programming specification:
> 
> /To activate the Programming mode, high voltage needs to be applied to 
> the MCLR input. Since MCLR is used for a
> level source, this means that MCLR does not draw any significant current./
> 
> So also don't worry about that one!
Ok, thanks for the reassurance!


Francesco


PS: probably the reply-to header field of the mailing list should be set to the 
"list" instead of to the "poster".
You can find this setting in the [general options] GNU mailman admin page of the 
mailing list, at the row containing "Where are replies to list messages 
directed?"...

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