SPI Packets

Decoder-to-Host Packet Descriptions

Vector Packet

The Vector Field follows the Address Field (see Appendix A). Each Vector Packet must be matched to its corresponding Address Packet. The ID of the vector packet is the word number where the vector word was received in the frame. This value corresponds to the WN bits sent in the associated address packet. The phase information must also match in both the Address Packet and the Vector Packet. It is important to note for long addresses, the first message word will be transmitted in the word location immediately following the associated vector.The word number (identified by b6 to b0) in the Vector Packet will indicate the message start of the second message word if the message is longer than 1 word.

There are several types of vectors:

•Short Message/Tone Only Vector

•Three types of Numeric Vectors

•Hex/Binary Vector

•an Alphanumeric Vector

•a Secure Message Vector

•Short Instruction Vector

Each is described in the following pages. A detailed description of the FLEX software protocol requirements is provided in Appendix A.

The Short Instruction Vector is used for assigning temporary addresses that may be associated with a group call.

The Numeric, Hex/Binary, Alphanumeric, and Secure Message Vector Packets have associated Message Word Packets in the message field. The host must use the n and b bits of the vector word to calculate what message word locations are associated with the vector. Both the message word locations and the phase must match.

Four of the vectors (Hex/Binary, Alphanumeric, Secure Message, and Short Instruction) enable the FLEXchip IC to begin the All Frame mode. This mode is required to allow for the decoding of temporary addresses and/or fragmented messages. The host disables the All Frame mode after the proper time by writing to the decoder via the All Frame Mode Packet. For any Address Packet sent to the host (except tone-only addresses), a corresponding Vector Packet will always be sent. If more than two bit errors are detected (via BCH calculations, parity calculations, check character calculations, or value validation) in the vector word the e bit will be set and the message words will not be sent.