ADK2012 audio output

Hardware Arduino Due
1

I'm trying to extend the USBHost/ADK lib to ADK2012. I'm interested in the audio output. Basically, I want to know the audio latency of such a solution.

So far, I find the correct interface (audioIf=1) & endpoint. I set the correct device configuration "1" (I checked this) and try to select the alternate setting that contains an endpoint (alternate setting altSet=1). However, if I check the active alternate setting, I get a 0 back.

The relevant code:

rcode = pUsb->ctrlReq(bAddress, 0 /* control endpoint /,
USB_SETUP_HOST_TO_DEVICE |USB_SETUP_TYPE_STANDARD| USB_SETUP_RECIPIENT_INTERFACE,
USB_REQUEST_SET_INTERFACE, altSet / valLo /,0 / valHi /, audioIf / index /, 0 / total /, 0 / bytes /, NULL / data /, NULL / read parser */ );
TRACE_USBHOST(printf("AndroidAccessory2::Init : set interface %d\r\n", rcode); )
if (rcode) {
goto FailSetConf;
}

delay(2000);

rcode = pUsb->ctrlReq(bAddress, 0 /* control endpoint /,
USB_SETUP_DEVICE_TO_HOST |USB_SETUP_TYPE_STANDARD| USB_SETUP_RECIPIENT_INTERFACE,
USB_REQUEST_GET_INTERFACE, 0 / valLo /, 0 / valHi /, audioIf / index /, 1 / total /, 1 / bytes /, &alt/ data /, NULL / read parser */ );
TRACE_USBHOST(printf("AndroidAccessory2::Init : alternate setting set %d\r\n", alt); )
if (rcode) {
goto FailSetConf;
}

I compared it with the code from the google ADK2012 download, but cannot find the difference/error. Any tips?

2

aleu:
I'm trying to extend the USBHost/ADK lib to ADK2012. I'm interested in the audio output. Basically, I want to know the audio latency of such a solution.

So far, I find the correct interface (audioIf=1) & endpoint. I set the correct device configuration "1" (I checked this) and try to select the alternate setting that contains an endpoint (alternate setting altSet=1). However, if I check the active alternate setting, I get a 0 back.

The relevant code:

rcode = pUsb->ctrlReq(bAddress, 0 /* control endpoint /,
USB_SETUP_HOST_TO_DEVICE |USB_SETUP_TYPE_STANDARD| USB_SETUP_RECIPIENT_INTERFACE,
USB_REQUEST_SET_INTERFACE, altSet / valLo /,0 / valHi /, audioIf / index /, 0 / total /, 0 / bytes /, NULL / data /, NULL / read parser */ );
TRACE_USBHOST(printf("AndroidAccessory2::Init : set interface %d\r\n", rcode); )
if (rcode) {
goto FailSetConf;
}

delay(2000);

rcode = pUsb->ctrlReq(bAddress, 0 /* control endpoint /,
USB_SETUP_DEVICE_TO_HOST |USB_SETUP_TYPE_STANDARD| USB_SETUP_RECIPIENT_INTERFACE,
USB_REQUEST_GET_INTERFACE, 0 / valLo /, 0 / valHi /, audioIf / index /, 1 / total /, 1 / bytes /, &alt/ data /, NULL / read parser */ );
TRACE_USBHOST(printf("AndroidAccessory2::Init : alternate setting set %d\r\n", alt); )
if (rcode) {
goto FailSetConf;
}

I compared it with the code from the google ADK2012 download, but cannot find the difference/error. Any tips?

Perhaps we just need common music player to output Audio via MicroUSB? What code do you use on Due side? I am also interested in Audio out via MicroUSB.

3

On the due side, I hacked the USBHost lib that comes with the arduino ui.

In the meantime, I got audio out working (more or less) by following the instructions in http://arduino.cc/forum/index.php/topic,139279.0.html. Audio output still stutters slightly and latency is high (> 200ms).

I also checked the switch to alternate setting based on that version. It seems like the android devices switch but don't report the correct alternate setting.

4

Why don't you just use ADK2012 IDE which already implement USB audio?