User's Manual

CDR-915 OEM DATA RADIO MODULE
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Revision O INTEGRATOR’S GUIDE
22
CDR-915 D ATA R ADIO
H ARDWARE TIMING
Ack-Back™ Handshaking
When configured for Ack-Back™ mode, the radio will attempt to resend packets that are
not acknowledged as received by the destination radio. While this virtually guarantees
that data will be correctly transmitted, there is still the possibility that the destination
radio is unavailable. Because of this, the CDR-915 supplies hardware indication of the
success or failure of Ack-Back™ packets. (See Radio Hardware Interface for pin
definitions)
Shown below is an example of the hardware handshaking for a successful Ack-Back™
transmission. The TX trace identifies the actual transmission attempt and is internal to
the radio. The SNDING trace is the handshake signal on Pin 9 of P2. This signal goes
high when the transmit attempt is made and stays high until the acknowledgement
packet is received from the destination radio.
Successful Ack-Back Transmission