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Subject: [ rockbox-Feature Requests-576656 ] Half duplex bi-directional remote idea

[ rockbox-Feature Requests-576656 ] Half duplex bi-directional remote idea

From: <>
Date: Tue, 02 Jul 2002 16:09:31 -0700

Feature Requests item #576656, was opened at 2002-07-02 16:09
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Category: None
Group: None
Status: Open
Priority: 5
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: Half duplex bi-directional remote idea

Initial Comment:
Here is an idea for implemening a remote control with display...

The ear jack on the recorder 20 is a 4 pole 3.5 mm plug. There is a serial port pin in additional
to the usual L+R + common. This pin is mapped to an async receiver pin on the SH1 processor and is
used as an input for remote control. (See previous suggestion - someone made a remote control for it).

What is really lacking is the capability of being able to output the song name etc info so that an external
display (e.g. dash board) can be connected.

Actually this can be easily be implemented using the single pin for half-duplex bi-directional
communication to an external microcontroller (e.g. PIC or Atmel is great for this) This has the advantage
that no hardware modification is needed on the Archos side - making this a more marketable product for
the average person.

- Put a pull up on the pin. Each side can only send data when the pin is high (i.e. line is idle)
- Once someone is talking on the line, wait until line is idle. Mean while buffer the data to be sent.
- When the SH1 wants to talk, it simply turn off the serial port and use the pin as an I/O pin and bit bang
the serial data out to the microcontroller. Once it is done, re-enable the serial receiver function.

Note: When it is sending data, the SH1 can actually send data at a faster rate as long as the
microcontroller can handle it. This is done so that the data is sent in a shorter burst.
The communication on the microcontroller side is handled by bit banging. A PIC or Atmel chip has
enough horse power to do this as well as driving a character LCD display or an external serial port.

Impact of this is a serial driver/display routine is needed on the Rockbox as well as a
microcontroller/keypad/display needed tobe developed.


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Received on 2002-07-03

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