Hardware question about vailable pins for CD changer emulator implementation

[shoora]

I noticed nice plugin for Archos players
"Alpine CD Changer Emulator" @ http://www.rockbox.org/twiki/bin/view/Main/PluginAlpineCDC.
This plugin uses bidirectionally programmed remote pin found on headphone jack. Signal level on that pin is 3.3 volt, which is OK for M-Bus interface.
I am not hardware engineer, but I have some (limited) background.
From what I see there HPREMOTE ADC remote control is not right choice. It's not bidirectional and it's ADC and probably may burn if I put some power on it. I hope that some pins on docking port I can use. Even pair of pin (one in and one out) will work as long as we can make small circuit to work with  BIDI port of Head Unit!
Anyone may help me with information?

And second - is there any way to powerup player when charger power detected? Some one must show that charger animation! And it must be some CPU code!

[toffe]

We could use the pin named RI Onkyo on the block diagram, there are gpio

The big problem is that we cannot find the connector to build our own interface.
I am looking for this for a long time now (check the logs at http://www.hack.id.au/files/gigabeat/irc/gigabeat/).

The only way is to buy some cable from toshiba but you have to unsold the connector (not so easy - 2x20 pin with a pitch of 0.6 mm)

Fyi : I am actually working on the usb host interface (should work directly with the original firmware but must be implemented on rockbox)

Any question or if you want to help on the hardware part, let me know
A great help would be to find the connector ref : QL11203-C638-7F from Foxconn

[shoora]

Last night I built cable using Toshiba E800 USB host cable. A also made small plugin to test GPIO pins.

I could not detect signal on pin18 (GPG7) Which is suppose to be Onkyo RI.
But GPG14 (USB/Line-out switch on cradle) on pin20 works just great for me!

Signaling
1. GPIO pins on Samsung CPU have type

Code: [Select]

 I/O type - tt8(phtbsu100ct8sm) 
 5V Tolerant Bi-directional pad, LVCMOS schmitt-trigger, 100Kohm pull-up
 resistor with control, tri -state, medium slew rate, Io=8mA

2. Now about signal levels on CD changer interface.
In one place http://kiora.ath.cx/alpine/ I read that Alpine uses TTL level.

Link Protocol:

   The Data Bus pin uses the Alpine AI-Net or MBUS protocol.
     It is a common bus using TTL signal levels:
       5v = logic 0
       0v = logic 1
     The head-unit maintains a logic 0 with a 22kohm pull-up resistor. (source: lost url?)

In another http://www.rockbox.org/mail/archive/rockbox-archive-2003-11/0476.shtml
...

The bus pin is pulled high to 12 volts with a ~2kOhm
resistor, pulses driven low. Because it's open collector, this is not harmful to the
Archos.
.......
The remote pin can be programmed bidirectional, that's the reason this
works. Very luckily the M-Bus uses a single wire communication and the two radios
I tried are happy with the 3.3 Volt level the Arcos can deliver.

and here... http://tamix.com/~davidh/mbus/

We connected the bus to the PC through a single diode. Data capture was done through the printer port (pin 10, ACK) which is internally pulled up by the PC. What happened was that when the bus went low, it would pull the PC data line low too, and when it went to 12V (too high for TTL used in the printer port), it just left the TTL input floating up to 5V. Simple, but it worked.

May I assume that it is OK to connect GPIO port directly to MBus? I don't remote control pin on Archos  any different from GPIO pin on Samsung CPU.

How to configure my pin (GPGCON) and should I pull it up (GPGUP) to inplement biderectional protocol? Or should I switch I/O port mode dynamically.?
I see description:

Code: [Select]

00 = Input 01 = Output
10 = EINT[22] 11 = Reserved

State 10=EINT[22] I assume is interrupt and configured by EXTINT1 and EINTMASK?

When the port is configured as functional pin, the undefined value will be read.

They mean that pin configured as interrupt (EINT)?

Software
Timer on Rockbox Gigabeat does not work

Code: [Select]

static bool timer_set(long cycles, bool start)
{
...
#elif CONFIG_CPU == S3C2440  /* TODO: Implement for the Gigabeat */
    (void)start;
    (void)cycles;
#endif /* CONFIG_CPU */
    return true;
}

Is anyone have plans to implement timers?
Am I right that interrupt vector on irq() function was set in crt0.S.

Automatic startup on DC plugin
Is it possible to put player into deep sleep instead of full shutdown?
And wake it up when power supply detected.

Playback control
My wife had Phatnoise box http://www.phatnoise.com/ in her car. Voice navigation they use is just perfect for mp3 player with HDD. Most of guys just associate disk number on head unit with some playlist. Phatnoise do navigation by disk1-playlists(disks)/disk2-albums/disk3-atrist and so on. Before timeout expires they accept NEXT/PREV keys on headunit to navigate across items in category. http://www.phatnoise.com/products/digitalmediaplayers/index_2.aspx?section=sectiontwo
Rockbox already have most of building blocks to replicate this interface and even more!