AT43USB325_05 Datasheet, PDF (70/109 Pages) ATMEL Corporation – Multimedia USB Keyboard Controller with Embedded Hub

8.1.10
Interrupt/Bulk OUT Transfers at Function End-point EP1, 2 and 3
The firmware must first condition the end-point through the End-point Control Register, FEND-
P1/2/3_CNTR:
Set end-point direction: clear EPDIR
Set interrupt or bulk: EPTYPE = 11 or 10
Enable end-point: set EPEN
The Function Interface Unit receives an OUT token from the Host with a DATA packet. The FIU
places the incoming data into the FIFO, issues an ACK to the host, and asserts an RX_OUT
interrupt.
1. Read UISR
2. Read FCSR1/2/3
3. Read FIFO
4. Clear RX_OUT
If more data:
Wait for RX_OUT interrupt
If no more data: set DATA END
Set UIAR[FEP1/2/3 INTACK] to clear the interrupt source
70 AT43USB325
3355C–USB–4/05