AT90USB646 datasheet(290/456 Pages) ATMEL

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7593L–AVR–09/12

AT90USB64/128

Figure 24-4. Example with OUT data banks.

24.14 IN Pipe management

The Pipe must be configured first.

When the Host requires data from the device, the firmware has to determine first the IN mode to

use using the INMODE bit:

• INMODE = 0. The INRQX register is taken in account. The Host controller will perform

(INRQX+1) IN requests on the selected Pipe before freezing the Pipe. This mode avoids to

have extra IN requests on a Pipe

• INMODE = 1. The USB controller will perform infinite IN request until the firmware freezes the

Pipe

The IN request generation will start when the firmware clear the PFREEZE bit.

Each time the current bank is full, the RXIN and the FIFOCON bits are set. This triggers an inter-

rupt if the RXINE bit is set. The firmware can acknowledge the USB interrupt by clearing the

RXIN bit. The Firmware read the data and clear the FIFOCON bit in order to free the current

OUT

DATA

(bank 0)

ACK

TXOUT

FIFOCON

Example with 1 OUT data bank

write data from CPU

BANK 0

Example with 2 OUT data banks

OUT

DATA

(bank 0)

ACK

TXOUT

FIFOCON

write data from CPU

BANK 0

OUT

DATA

(bank 1)

ACK

write data from CPU

BANK 0

write data from CPU

BANK 1

write data from CPU

BANK0

Example with 2 OUT data banks

OUT

DATA

(bank 0)

ACK

TXOUT

FIFOCON

write data from CPU

BANK 0

write data from CPU

BANK 1

write data from CPU

BANK0

OUT

DATA

(bank 1)

ACK

AT90USB646 Datasheet(PDF) 290 Page - ATMEL Corporation

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