more Rockbox things on the german homepage of Uwe Freese
Attention: Be careful when modifying your Jukebox. I don't guarantee anything. If you destroy the device, it's your fault. It's always a good idea to practice modifying devices and especially soldering with old worthless electronic parts.
All Archos Jukebox Recorders have a real time clock (RTC) which has an alarm function. That means you set a time in the RTC memory, switch on the alarm function with setting two flags and at the given time, the alarm output pin of the RTC (/IRQ) goes to low voltage (it is an open drain output).
An unmodified AJB has this /IRQ pin connected with the CPU. It could be used for timing functions. But it isn't - at least in Rockbox. Also the original Archos firmware doesn't seem to use this function.
A nice thing would be to use the alarm as system wake up function. With an unmodified AJB, this is not possible, because there is no appropriate circuit in there. With this mod, you can add this functionality.
To use this feature in Rockbox, add -DHAVE_ALARM_MOD in the EXTRA_DEFINES section of the Makefile in your Rockbox source code directory and recompile it (the code you need for the alarm is already in the source code). You can download a precompiled version in english or german (CVS version from 10.01.2003). You can test this version also with an unmodified AJB to see how the feature behaves.
In Rockbox, you'll find a new option Wake-Up Alarm in the main menu. The usage is as follows:
There's a demo video available that shows the usage of the alarm function (DivX 5.0 format, 1 MB).
Pin 14 of the RTC is an open drain output and is connected with a pull up resistor. If the alarm goes on, the gate of the transistor (any PNP type should work) gets a voltage < battery voltage and switches + battery power to his output (to the ON switch).
Read the description disassemble the archos on the rockbox homepage.
Here is what you have to take away for this mod:
take away the
de-solder the left metal angle
be careful with the
two thin wires
I suggest to also take away the harddisk for better handling. After this, your AJB looks like this:
You need to solder cables to three points.
Test if the soldering point is the correct one with connecting a continuity tester to the + pin of the batteries.
The two upper pins of the switch in the picture are what you need. The lower two pins are connected to + of the batteries.
Bend the /IRQ pin carefully upwards and connect a wire to it. Maybe you want to practice this with some ICs on an old motherboard.
Solder the additional circuit and isolate it completely with heat shrink tubing.
connect two resistors
isolate the pins
other wires and
then push the whole thing
between the two circuit boards
Now install the Rockbox version with alarm mod support and try if all works correctly. Then close your device and have fun. :-)
Generally spoken, there are some characteristics in this mod which could lead to a problem. But don't be afraid - my implementation in Rockbox makes sure these problems don't occur!
If the alarm is on, the ON switch is pressed. If this ever happens when the device is on, your unit is locked (the same as pressing the ON key forever manually) and you can't turn it off with pressing the OFF key. This could be especially a problem when using the original Firmware (if it uses the alarm as watchdog timer, the /IRQ pin is connected with the CPU if you haven't done the mod), although it seems it doesn't use the alarm.
Another problem could be if one wants to use the RTC as a watchdog timer for the CPU in Rockbox. This is not possible any more with the mod, because (as described above) you cut this connection from RTC to CPU.
So a "perfect" mod that cannot lead to this problems would be:
And that's why I didn't make it this way:
For general questions and support for your Archos Jukebox and if you have problems with your device, use the Archos Technology homepage.
For discussions and bug reports about Rockbox use the Rockbox mailinglist and the Rockbox site at Sourceforge.
Concerning this mod or the other stuff on my page, you can write me an email.