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nRF24AP2-USB Product Specification

Figure 15. Status stage

The status stage is used to verify the status of the overall request. For a control write transfer the status

stage will start with an IN token packet. The nRF24AP2-USB will reply with a DATA packet of zero length

if the overall request was successful. A STALL will be returned if an error occurred at any point during the

processing of the transfer. A NAK will be returned if the nRF24AP2-USB is still busy processing the trans-

fer. Finally the host will send an ACK handshake packet to indicate that it received the status.

5.3.6.2

Control read transfer

Figure 16. Setup stage

The setup stage starts with a SETUP token packet, followed by a DATA packet detailing the type of

request. Finally an ACK handshake packet is sent back by the nRF24AP2-USB if the setup data has been

received correctly, otherwise nothing is sent back.

Figure 17. Data stage (optional)

When the request indicates that the host wants to receive control data, the data stage will be made up of

one or more IN transfers. Each IN transfer will start with an IN token packet. The nRF24AP2-USB can

reply with a DATA packet, a STALL indicating an error has occurred or a NAK indicating that the data is not

DATA0

(0 Bytes)

IN

ACK

STALL

(error)

NAK

(not ready)

ACK

SETUP

nRF24AP2-USB

Host

DATA0

DATAx

IN

ACK

STALL

(error)

NAK

(not ready)