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Subject: Re: firmware/serial.c mod problem. please help.
From: [IDC]Dragon (
Date: 2004-04-20

> the idle serial level is 1, the start bit is 0...
> how are these serial level at the TTL side and in the RS232 side?

On TTL, 1 is high and 0 is low.
On RS232, 1 is -12V and 0 is +12V.

> are the RS232 levels inverted compared to TTL?


> In my case, I connected the pic output directly to the serial Rx of my
> PC and it works.

This is strange. Maybe the PIC has an option to invert its TX?

> As the serial driver is in software, I dont remember the levels I used,
> but I think it is inverted.

Ah, that explains.

> Does this mean I need at least an inverter (or a rs232 adapter) for the
> archos to transmit to the PC?

Yes. As a minimum solution, a transistor can do it.


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