Roger Duffus wrote:
>
> Hello All,
>
> I have a question about the Pic 16f877. First let me explain the circuit. I
> am using the Romzap programmer to program my 877. I have port d pins 4-7
> connected to some ir transmitting circuitry(4 identical circuits). The
> transmitting circuitry consists of a 1K resistor connected to the base of a
> 2n4401 transistor and the other end to the port pin. The emitter is grounded
> and the collector is connected to 3 ir transmitter leds in series and a 10
> Ohm resistor. The problem is that when I try to connect to the Romzap, the
> program that I originally burnt on to the chip starts running. Romzap also
> says that it is "Connected to Boot loader" but it is not actually connected.
> I think that the circuit is draining too much current and is causing a
> communication problem with the Romzap(PC). I think this requires some
> carefully placed capacitors. Does anyone have any suggestions?
>
> Regards
>
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Hi Roger,

Perhaps take out the 10R resistors leaving the LED open circuited, and
see what happens.

Alternately, recalculate the resistors and connect the LEDs to the
supply rail before the 5V reg.

--
Best regards

Tony

mICro's
http://www.picnpoke.com
mailto:sales@picnpoke.com

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