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nRF24AP2-USB Product Specification

When the host is ready to receive bulk data it will send an IN token packet to the IN endpoint (0x81). The

nRF24AP2-USB will either send a DATA packet if one is ready, send a STALL if an error occurred, send a

NAK if it no data is ready yet or do nothing if the IN token was not received properly. Finally the host will

send an ACK handshake packet if it successfully received the DATA packet.

Figure 20. Bulk OUT transfer

When the host wants to send bulk data to the nRF24AP2-USB it will send an OUT token packet to the OUT

endpoint (0x01). This will be followed by a DATA packet containing the bulk data. If the nRF24AP2-USB

received the data successfully it will return an ACK handshaking packet. If an error occurred during pro-

cessing, the nRF24AP2-USB will return a STALL. If the nRF24AP2-USB is still busy processing the previ-

ous DATA packet, a NAK will be returned. If any part of the OUT token or DATA packet was corrupted or

missing the nRF24AP2-USB will do nothing.

5.3.7.2

Bulk transfer example

The libraries available from ANT contain all the supported messages to configure and use the nRF24AP2-

USB. Figure 21. shows an example of a serial message passing between the host and device.

In this example the host issues an ANT_RequestMessage() in the data packet to read the ANT version of

the device. We have included hexadecimal values to help you should you need to debug the host serial

interface.

Figure 21. Example of OUT transfer (with varying level of detail)

Figure 22. Example of IN transfer (with varying level of detail)

ACK

OUT

DATA

STALL

(error)

NAK

(not ready)

nRF24AP2- USB

Host

ACK

OUT

DATA

ANT_RequestMessage(0x3E)

”A4 02 4D 00 3E D5"

ACK

IN

DATA

ResponseFunc (-, 0x3E)

”A4 0B 3E 41 50 32 55 53 42 31 2E

30 34 00 ED"