[MPlayer-users] Re: [m68HC11] Reset

[by way of Technical Operations <teck@charter.net>]

Hi Hugues,

> Yes I build my own hardware on a testing board.  My circuit work for a
> while but now I have a problem that I can't find.

Ah, that's strange. It worked for a while. Mmhh, are you sure, your Pins MODA
und MODB are in right position?

What was the last modification on the hardware? Or came the problem "over
night" ?

> My reset circuit is done with a DS1233;   1 pin to ground, 1 pin to
> Vdd(+5v), 1 pin to the pin 17 on the MCU(68hc811e2) with a 1uf capacitor to
> the ground.

I picked up the datasheet and it's so simple.

Pin 1 Ground
Pin 2 Reset\
Pin 3 Vcc
Pin 4 Ground

But I think, that's not the problem. Just look with an oscilloscope on pin 17
on the MCU, then press reset. That's the best way to be sure if the hardware
is ok.

> Can you send me a schematic of your reset circuit?

I just use a different IC and it doesn't really matter what kind of reset IC
you are using. They all work fine and million times.

> > The next, you can use LEDs to indicate RxD und TxD on your RS232 IC. =>
>
> Can you send me a schematic or explaination?

Take two LEDs, from Pin 20 and 21 (Kathode) over resister 220R to Vdd(+5V).

If you press the reset button and hold it down, both LEDs are off. Release
the reset button, RxD is still off and TxD in on. Voila, if so, the MCU is
ready to connect via RS232.

> could test it?  PD1 = 0101010101...????

You can look with the oscilloscope on pin 20, 21 for aktivities after reset.

James

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