Datasheet

8.3 What if I need design assistance creating

my accessory?

If you have questions about the library, our parts, or any of our reference codes/boards, please feel free to contact Microchip

for support (What if I need more support than what is here? ( see page 48)).

If you need someone to assist you in creating a portion of your design, Microchip has design partners that can assist in the

portion of your design that you need help with. You can find a list of design partners at the following address:

http://microchip.newanglemedia.com/partner_matrix. At the moment there isn't an option to filter for Android specialists. The

best option to filter by right now is USB.

8.4 The firmware stops working when I hit a

breakpoint.

The USB protocol has periodic packets sent out that keep the attached device active. Without this packet, the bus goes into

an idle state. Normally when a breakpoint is hit in the code both the CPU and all peripherals halt at that instruction. This

causes the USB module to stop running resulting in the attached peripheral to go into the idle state. The firmware still thinks

that the peripheral is active. This results in a break in communication.

There is a way to tell the microcontroller to leave the peripheral enabled when a breakpoint is hit. This will allow the USB

module to continue to run and sent out the Start-of-Frame(SOF) packets required to keep the bus alive. This is done via the

following methods:

MPLAB 8

Under the debugger->settings menu option, select the "Freeze on Halt" tab. Uncheck the "USB" or "U1CNFG" setting in the

list. If neither of these items are in the list of peripherals, uncheck the "All other peripherals" option at the bottom of the list.

MPLAB X

Go under "File->Project Properties". In the project configuration window, select the project configuration that you are using.

Under that configuration, select the debugger that is in use. In the resulting debugger menu, select the "Freeze Peripherals"

option in the drop down box. Uncheck the "USB" or "U1CNFG" options if you see them. If you don't see these options,

uncheck the "All other peripherals" option.

8.5 If I hit the "Home" or "Back" buttons while

the accessory is attached, the demo no longer

works.

If you hit the "Home" or "Back" buttons while the accessory is attached and the demo no longer runs, the code likely tried to

close the FileInputStream to release control of the accessory. v2.3.4 and v3.1 of the Android OS have an issue where

closing the ParcelFileDescriptor or FileInputStream will not cause an IOException in a read() call on the FileInputStream.

This results in the ParcelFileDescriptor being locked until either the accessory detaches or until the read function returns for

Microchip's Accessory Framework for Android(tm) 47