firmware of device controller for ISP1362 chip

hi,

I'm modifying the coding from DE2 board CD -> DE2_demonstrations -> DE2_NIOS_DEVICE_LED.

For the firmware of device controller for ISP1362 chip, there got six related coding: MAINLOOP.C, CHAP_9.C, D13BUS.C, HAL4SYS.C, HAL4D13.C AND ISR.C.

Where HAL4SYS.C and HAL4D13.C is hardware abstraction layer;

ISR.C is interrupt service routine;

CHAP_9.C and D13BUS.C is protocol layer;

MAINLOOP.C is mainloop.

Does anyone knows which firmware coding need to be modify and which one remains if I want to change the USB data block transfer to 16 bytes data block?

Thanks and regards,

Summer